For some reason the stones acquired the reputation for cure of kidney problems and were dubbed "piedra de yada" for "stone of the loins". This name passed into French as "le jade" and so into English as the familiar jade.

In a similar historical quirk the Spanish phrase became, in Latin, "lapis nephriticus" and gave us our word nephrite, though now we recognize the two stones as different chemically – and no cure for the kidneys!

Those of us who have tried to shape jadeite may well sympathize with the ancients! It’s fibrous, tough and hard at 6.5 to 7 on Mohs scale with a specific gravity (SG) of 3.33 – heavy as rocks go. Geologists have snapped many a wooden hammer handle trying to chip off a piece, a fact that in itself may provide a crude field test!

Nephrite is difficult to tell apart because it too is hard at 6.5, has a gravity of 3.0 and may have similar colours. But nephrite is inclined to be "muddier" in its colours and its range of colours more limited.

Though both stones may be white to colorless, they may also be green, mauve, blue, brown, yellow, red, gray and black due to impurities of iron, chromium and manganese etc. The most cherished colour is "mutton fat" white, and the famed "imperial green" is also held in particular esteem.

Though power tools and modern abrasives are now used, the ancients, presumably with ample time on their hands, used tubes of sand-filled bamboo to drill holes and natural grits like crushed garnet (H7) and corundum (H9). Using leather thongs drawn back and forth, these natural abrasives could also be used to cut slices from crude blocks. Neither stone can be flaked like flint to make knives and weapons but when so ground and shaped they take a keen tough edge for axes, arrow points and knives. So where do these wonder stones come from? In short, from high-pressure zones at a depth of 30 km, deep in the crust. They are related to serpentine, the host rock of asbestos and also to tremolite and actinolite.

And where to find them? Upper Burma is still the source of most gem quality jadeite, with minor amounts in California, Japan and Guatemala. Nephrite is more common – though still rare: China, Russia (Lake Baikal region), South Island of New Zealand, Poland and here in Canada, the Fraser River near Hope, B.C. This latter area presently enjoys a brisk trade with the Orient, thus completing the circle of fame of the jadestones.

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Ammolite is actually the shell or nacre from a long-extinct marine cephalopod, the ammonite. These flat-coiled animals, the grand-daddies of the modern nautilus were once so prolific that their numerous species are widely used to define the stratigraphy – rock layers – of the Jurassic Period and parts of the Cretaceous Period – about 180 to 65 m.y.B.P.

This particular species is the Cephalopoda ammonoidea of Cretaceous age. A typical specimen is about 30 cm in diameter and 10 cm thick, though "baby" ones are found too. What is so interesting about this type is the excellent preservation of the shell, because almost always this fragile calcite-aragonite nacre is destroyed leaving only the stone cast of the form.

The iridescent nacre is only a few millimeters thick and very fragile – so great care must be taken to nudge it off the stoney parts. Even then large pieces are rare. The useful fragments must be cemented into doublets to resist the stresses of jewelry. Some well-mounted pieces rival the beauty of fine opals and may well be of similar price.

Trade names may confuse us, like "calcentine" and "korite". Dealers in Lethbridge, Alberta may help you find suppliers.

Trouble identifying that precious piece that you tapped out of the quarry or dump? Don’t despair, if you’ll settle for a rough field estimate, but you’ll have to resort to more sophisticated tests if you want to be precise. So these are field tests only:

1. Habit – is it flat and scaly like mica or in a crystal form? Crystals of unusual size and shape are rare – they are in museums! Since there are some thirty variations of the crystal systems, few of us are qualified to judge. A poor field use, though some forms are useful e.g. quartz.
0. Colour – useful in some cases but not reliable. Beware of oxidation or tarnish which hides the true colour. Also many minerals come in many hues e.g. quartz, calcite.
1. Lustre – the way light is reflected from a mineral. Of very little field use.
2. Opacity – or transparency. Metallic minerals are opaque. Some transparent ones may be potential gemstones. Beyond sorting out the metallics, this property is of limited use but don’t toss away any emerald, topaz, ruby or sapphire!
3. Specific Gravity – or SG is of some use. Most metallics run about SG 3 to 4. "Stony" minerals are about 2 to 3. If it comes in over 6, stake a claim! Most dumps don’t offer specimens large enough to "heft" for us to judge. Use at least a good "thumbnail" size.
4. Streak – press a piece across unglazed tile & note colour of powder. Very useful! Cuts through tarnish.
5. Hardness – or H. Get to know Mohs scale! This is a very useful quality and usually the first test one makes. Keep that knife handy! While many minerals may be similar, this test is great for sorting out the two great stoney groups – calcite/limestone etc. and quartz. Hardness alone may at least put you on the right track. Good for metallics too – try pyrite vs. gold (6.5 vs. 2.5). Excellent first test but some minerals are harder in certain directions. E.g. kyanite; 4-5 lengthwise, 6-7 across the crystal.
6. Cleavage – not the burlesque type but the way a piece breaks. Shell-like (conchoidal) yields sharp shards (as flint). Some yield smooth flat breaks (as micas) and some are partly smooth & rough in different directions (as feldspars). The quartz group – chert, flint, amethyst etc. – have very rough breaks. So do garnets. Of modest use but good for feldspars, quartz, micas, calcite, galena and halite for examples.
7. Acid – use 10% HCl (hydrochloric or "plumbers" acid) in squeeze bottle. Excellent to verify the carbonates from almost anything else, especially the quartz family. Great for limestone vs. dolomite. Fizzes slowly on cold rock. Warm it up first.
8. Oddballs – Taste – don’t lick everything – there is lots of arsenic around! Great for halite and potash salts if you suspect them.
9. Oddballs – Magnetic – very useful for picking out magnetite, ground-up pyrrhotite (an iron sulfide). Use a horseshoe magnet suspended on a string.

Oddballs – Fluorescence – of some use (in the dark) for fluorite, some calcite, scheelite and sphalerite .. Oh yes! And diamonds too!

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As brimstone, the fiery fate of evildoers, sulphur is mentioned at least six times in the bible.

We are quite familiar with the bright yellow color and the common orthorhombic crystals. It is soft at H2 and very light, SG about 2. It ignites easily – one reason it’s used in matches – and burns with a blue flame, giving off very pungent fumes.

Elements which combine with sulphur are chalcophiles (sulphur loving) and many useful elements – iron, nickel, copper, lead etc. are tied up with it. And we are all familiar with the results of tearing these compounds apart -–sulphur dioxide – which combines with moisture in the air to yield acid rain.

So depending on how we treat it, sulphur is a blessing or a curse. When tamed, most of it goes into making sulphuric acid, one of the most important industrial chemicals.

Hydrogen sulfide gas (H2S) is lethal at concentrations as low as .08 percent, is very corrosive to metals and doesn’t endear itself with its "rotten egg" odor. Oddly this stink of sulphur in mercaptans is used to save us from leaky gas lines and propane – it’s added to our fuel to warn of leaks.

Sulphur in H2S gas is a devil for the petroleum industry. Crude oil almost always has some S – after all petroleum comes from organisms – from about 2% by weight to common 5%. One deep well known to this writer in the Alberta foothills came in with 90% H2S – so much that as the gas reached the surface and expanded, raw sulphur soon plugged the well shut.

Hydrogen sulphide, therefore, must be removed before natural gas can be used and it is, in vast amounts. There are over twenty gas plants in western Canada each removing sulphur; seeing has to be believing. Visualize a block of sulphur one city block (or more) wide by two city blocks long (or more) and perhaps 10 storeys high at many plants and one can readily see why Alberta is the world’s greatest producer of sulphur from natural gas.

The United States is the greatest producer of sulphur, in this case from buried salt domes where it accumulates in the cap-rock. Hot water is pumped down one pipe to dissolve the sulphur, and returned up another, the Frasch process.

And don’t forget gunpowder, fireworks, paper, rubber, insecticides and medicines. Sulphur has its good sides too.

In our long-ago first lessons in geology and minerals – remember? – we were told the difference between a rock and a mineral. Confusion persisted, and it became worse when we learned that they could both be the same – a rock is made up of mineral(s). But when you have a million tonnes or so of almost the pure stuff, are they a rock or a mineral – or both?

In fact, early geologists were so impressed with the chalk cliffs of England that to name them was easy – Creta. From this to "Cretaceous" for the age (era) was a nice fit in the burgeoning geological time scale. Once the grand age of the earth was recognized early geologists put a date of about 70 to 135 million years before the present (B.P.) on these rocks based on fossils. Modern science confirms those estimates.

The "type area" – where chalk beds are especially well developed – is just where you and I would expect it – the white cliffs of Dover – in southeastern England. From there, they are easily traced across – under – the Channel to France and Belgium. In our western plains are two thin "marker" beds of great use to petroleum geologists. These "white specks" are in fact of the same material as is chalk and extend south into Texas, joining to form thick beds.

From our kiddy days we learned of chalk as a teacher showed us the wonders of the alphabet. But it has very important industrial uses too: in cement and lime, as fertilizer, ceramics, putty, cosmetics, rubber, paper, toothpaste, and fillers in food (!) and medicines.

Why the Cretaceous should be so marked by chalk is uncertain but we do know that it’s made up of marine organisms and processes. The fossil parts are calcareous remains of minute animals as foraminifera and plates and discs of algae – coccoliths. There are some larger organisms represented too such as ammonites and sponges. These latter in fact are, along with siliceous radiolarians, the source of chert which forms a myriad – as in millions! – of flat nodules about the size of flat tennis balls. These are either scattered through at random or often lie along planes in the chalk. The chalk matrix is soft, friable (crumbly) and very porous. It is mostly of fine particles of calcite precipitated from – probably – warm marine waters. Surprisingly it is little changed to what we’d expect, limestone.

Chalk beds have had a profound impact on history too. Early man found that these chert/flint nodules could be shaped into razor-sharp bits and so give arrow points, spear heads, axes and "knives". Thus was born the Stone Ages, and the sites of these ancient flint "mines" can still be seen in England. More modern man has found that walls of flint nodules last for hundreds of years.

The exposed edges of chalk beds in Northern France have a darker side too. Millions of tons of exploding shells of especially WW1 churned into chalk mud the trenches and no-man’s-land. The graveyard of a generation of soldiers.

On the brighter side, the drilling of the famous "Chunnel" under the English Channel was infinitely easier in the same great chalk beds 60 metres under the bottom. And that is good.

From the swish of sand on the beach to the grind on our teeth from unwashed spinach we recognize this ubiquitous mineral. (Technically, "sand" is a size of grain and may be composed of any mineral.)

Quartz is the most common form of silica but one book lists over two dozen varieties depending on a host of impurities and crystal forms from the beauty of near-perfect hexagonal prisms with pyramidal ends to dense fibrous masses of chalcedony.

The uses for quartz in one form or another fills pages. In geology it takes on one form – alpha – at temperatures below 573° Cand beta at temperatures to 870° C. It has vast industrial use from a filler in pills – powdered form of course, to cement for concrete to the lapidarists’ favourite material. Part of this list includes: amethyst, rose, yellow, smoky, cat’s-eye, aventurine, jasper, carnelian, chrysoprase, agate onyx (true onyx not the carbonate "trade" variety), flint and many exotic varieties.

Flint and chert have been used since ancient times to chip into weapons and tools and to strike sparks for fire and firepower. Did you know that the Kakabeka Falls at Thunder Bay tumble over layers of very hard Precambrian rocks appropriately named the Gunflint Chert?

Chemically this compound is simple enough, being just sodium (a soft metal) and chlorine, a very unhealthy gas to form NaCl. Masses of it break into neat cubes (it’s isometric), soft at H2.5, average SG at 2.16 – and it tastes great!

Now that we’ve disposed of the dry facts, let’s look at other aspects of salt.

When we get ill we often get a saline drip. Why salt? It’s been suggested that the salt in our blood is a relic of our ancient born-in-the-sea heritage. And a proper balance of salt (and potassium) is still critical to our well being. We crave it and sometimes go to great lengths to get it. There are 3500 parts of salt in a million parts of average sea water – millions of tonnes – and vast amounts underground in fossil form but we can’t always get access to it. Yes, one can drink camels’ urine in desperation as has been done in the desert, but happily there are more pleasant ways to get salt.

In ancient, almost land-locked bays and lakes salt-bearing waters evaporated along with other salts like gypsum, anhydrite, sylvite and carnallite – the latter two being valuable potassium (K) salts. Beds hundreds of metres thick were later buried to form vast reserves of these minerals. Saskatchewan is a major supplier of potassium salts for fertilizer; it’s Devonian in age; southern Ontario is a great producer of salt from Silurian beds. Many hot countries draw salts into shallow ponds to evaporate seawater. In hot dry Iran "glaciers" of Cambrian salt have been squeezed to the surface by tectonic pressures because halite flows under pressure, like putty.

One of the most interesting aspects of salt is its appearance in salt domes, the most noteworthy being those around the Gulf of Mexico. Here are great beds of ancient salt, some as deep as 16,000 m (from seismic exploration). Somehow these become warped and initiate plastic flow, eventually forming towering "bubbles" – much like those seen in lava lamps. Since the SG of salt is less than that of the enclosing clay and sand beds, it tends to float upwards. In doing so these rising domes bend the overlying beds forming excellent traps and prolific oil and gas reservoirs. Some even reach near the surface where they are mined, not only for halite, but also vast amounts of sulphur which often cap these great "balloons".

In Roman times, the army was paid partly in salt and later the money allowance to buy their own salt appeared as salarium, from which we moderns – if we are fortunate enough – now draw our salaries.

Some of that salary may go to replace that rusting car in our garages, thanks to the ravages of road salt. On the plus side we get washing soda, baking soda, caustic soda, hydrochloric acid, bleaching powder, preservatives, flux, glass, glaze and soap.

Pass the salt, please!

We all know that calcite stands for number 3 on Mohs scale between gypsum and fluorite, that it’s easily scratched with the knife, that it fizzes readily in dilute acid. It’s also kissin’ cousin to aragonite which forms the shells of many clams and brachiopods. Calcite has more forms and habits than any other mineral and add to that a wide spectrum of colors from clear to black. But the streak is always white or a pale color.

A variety called Iceland spar is strongly doubly refractive which means that a clear cleavage piece, when laid on a mark on paper will display two separate images. This property was put to good use in pre-Polaroid days in polarizing microscopes – Nicols prisms. A suitably pure piece was sliced in a special way, one piece mounted in the tube and the other under the rotating stage. Thin sections of rock when placed on the stage displayed useful colors and shapes.

The different varieties of calcite may be grouped like this: ordinary calcite; limestones, marbles, chalk and marl, and spring, stream and cave deposits. These groups deserve fuller discussion but for now the notes will be limited to one or two.

This mineral is the basis of limestone, itself of many kinds. Worldwide, most limestone is marine in origin – laid down in warm shallow waters. While fossils play quite a role in many deposits, drawing calcium carbonate out of seawater, much limestone just precipitates out. This is because cold seawater – any water – holds vast amounts of this compound in solution. But if this water warms up in shallow basins like the Persian Gulf (or our teakettles!), the mineral comes out as very fine grains and crystals; this may be the start of chalk. Even fish disturbing such saturated areas may leave a milky trail of precipitating calcite.

A famous example of this fine "lithographic" limestone (yes it once was used to make printing blocks) is in Solenhofen, Germany. It’s so fine grained that the imprints of even leaves and insects are preserved in exquisite detail. We’ve all heard about Archaeopteryx, the earliest (Jurassic) bird.

A famous limestone comes from the Ordovician (age) near Winnipeg. This Tyndall rock is used throughout our parliament buildings and hundreds elsewhere. The mottling is considered to be dolomitized feeding trails of animals.

Under suitable conditions calcite transforms to marble, either sugary or very fine in texture. Its use ranges from underfoot as chips in terrazzo to the glories of Michelangelo’s "David" in Florence. And why not? Nearby are the 200 quarries of famous Carrara marble. After 200 years over a million tonnes a year are still produced, mostly for buildings.

During WW2, to curry favor with Hitler, Mussolini presented him a birthday gift for his "Eagle’s Nest" at Berchtesgarden – a huge slab of red marble for the lintel of the fireplace. Ugly, its only virtue was its richness in ammonite (Jurassic?) fossils. Hitler hated it!

If you have ever dropped mercury you can probably kiss it – but only figuratively! – good bye. After all it’s not called quicksilver for nothing. In fact, its Latin name is hydrargyrum which means "liquid silver" and whence comes its chemical symbol Hg.

Mercury is the only liquid metallic element though it is not often found as such. When it does occur it is as droplets, usually associated with its major ore, cinnabar, HgS, mercury sulphide. The liquid is easily obtained from the ore by roasting in air and condensing from the furnace gases. Since its not easily oxidized, mercury stays put as the shiny liquid. When frozen at –40° C, the X-ray shows a rhombohedral structure. It’s very heavy too, with SG 13.6.

It has many useful properties. With high surface tension it promptly rolls itself into balls, which gives a spill its "mercurial" speed. It doesn’t wet glass like water does so it’s useful in thermometers except in Arctic winters where it freezes at – 40° C (this is where the typical alcohol thermometer takes over). But alloyed with thallium (Tl) it can be used to –60° C. Since it easily conducts electricity, it is widely used in sealed switches in thermostats etc. It’s widely used in industry in fungicides, in batteries, barometers and thermometers, in rectifiers to convert AC current to DC and, in vapor form in fluorescent lamps. Here, its rich output of ultraviolet rays cause the coatings to glow brilliantly.

It easily forms amalgams with silver – as in dental fillings – and gold. It is still used to recover fine gold from placer panning, the gold being retrieved by boiling the mercury off, often into the air where it may be breathed with lethal results. Read about Amazon gold panners.

Rather common from hardrock decay and mill tailings, mercury forms dangerous compounds in lakes and ponds & may be taken up in the food chain as in fish. It lingers long in the brain doing permanent damage. Recall the Minimata disaster in Japan a few years ago?

Paradoxically mercury can also be tailored into useful medicines in ointments, mercurochrome, and once-upon-a-time in calomel (mercurous chloride). Then there was the infamous mercury-and-sweat "cure" for syphilis.

Mercury fulminate is an extremely sensitive explosive when dry. This gray sandy powder was until about 1960 used in detonators to set off bigger charges, a use pioneered by Alfred Nobel, he of dynamite, in 1867. Two world wars have been "successfully" pursued with shell fuses like this. Now a more stable replacement has been devised (making war "safer"?) – lead azide.

Cinnabar is a carmine red, granular to earthy coating and once used as facial rouge (!). The major world source is Almaden, Spain with lesser amounts in many places including California and British Columbia.

Judging by the outpourings of honour and respect heaped on the late Mr. Trudeau, he is certainly due a permanent and substantial monument. Only history will weigh the respective merits of his achievements and those of Sir William Logan after whom the mountain is presently named.

But old-timers may recall the backfire when Castle Mountain, near Lake Louise, Alberta was re-named by euphoric politicians Mt. Eisenhower. This respected Supreme Commander of Allied Forces during WW2 also deserves to be remembered but it was folly to select Castle Mountain which after all does look like a castle. The public rejected the idea and Castle Mountain it is.

The name change especially abraded the tender sensitivities of geologists who have long cherished Castle Mt. as a fine display of Precambrian and Cambrian age rock hoisted up on a grand far-traveled fault slice.

The center of all the fuss, Mt. Logan, is one of the great peaks – the highest- in the St. Elias Mountains near the Alaskan border. At 6050 meters elevation (distance above sea level) it is at the heart of one of the great mountain belts of the world. It is the highest point in the Yukon on a block supporting at least four others over 5500 meters. They are surrounded by wide ice-filled valleys and snowfields down to 2100 m. Some even flow down to the sea, to the delight of cruise-ship tourists.

Only Mt. McKinley in Alaska is higher at 6190 m. Mt. Logan lies within the Kluane (klu-ah-nee) National Park. If you find the temptation to visit irresistible, count on adventure and expenses. Visitors insist that it’s worth every dollar. Most travelers drive there on the Alaska Highway. Others, bringing their own vehicles, come by ferry from, say, Vancouver, up the spectacular Inside Passage to Haines, Alaska, then drive the 256 km to the Park entrance at Haines Junction, Yukon.

So, a tip of the peak to you Sir William and ……..

Leave ‘er be.

While minerals are the core of most of our collections – colors, crystal forms, rarity? – fossils can be just as fascinating in form and rarity, though rarely colorful. For these reasons some of our members are devoted to fossils and their histories.

Happily these parts of southern Ontario are rich in the preserved remains of (usually) extinct creatures. There is a vast literature on the searching; classification and history of fossils and readers are encouraged to seek these out at libraries and shops.

Geological specialists called stratigraphers rely very heavily on fossils as they try to match (correlate) formations of rocks in one area with those in another, often hundreds of kilometres – or even continents – away. So, far from being objects of mystery and superstition to the ancients, today fossils are essential to revealing the relative ages of rocks. Of course this method is now backed up by the more precise radiometric technique.

The relative dating system, being all early geologists had, was first put to formal use in the superb work of William Smith’s map of 1815, finally published after years of observing rock layers (strata) as he built canals. This, after all, was the time of the great Industrial Revolution when coal was king and steam began to frighten horses (and people too!).

This was the time too when that great concept, the geological time scale, was being hammered out – bitterly at times. Now it is not only useful but essential for putting time and fossils into perspective. Collectors take note!

In these parts of Ontario (Toronto-Brampton-Niagara) we live on the eastern edge of a grand "saucer" tilted to the southwest on a great thickness of Ordovician carbonate rocks (limestone and dolomite) shale and sandstone. Farther west on the Escarpment are stacked rocks of Silurian age (See? You do need the time chart!). The top of the Ordovician, by the way, is marked by a brick-red (sometimes green-mottled) shale named Queenston Shale – a superb "marker" bed but with no visible fossils.

Still farther west e.g. London, are still younger Devonian beds (Sarnia’s oilfields) and farther, some Lower Carboniferous (Mississippian) rocks. So the great span of time represented here is happy hunting for collectors with rock ages from 440 m.y. to 260 m.y.

To get started herewith is a skeleton list (pun intended) useful in road cuts, stream valleys and on shores. Write to your editor for more details:

Ordovician and Silurian – graptolites (in black shales), trilobites, crinoids, cephalopods (long cones, some coiled), gastropods (snails), pelecypods (clams), brachiopods (like clams but oddballs).

Devonian – gastropods, pelecypods, brachiopods, corals (solitary horn shaped and colonial honeycomb and chain types).

But bear in mind. The time divisions are man-made. These ancient creatures weren’t smart enough to oblige and often "slopped over" from one age to the next. Well, who’s to quibble over a few million years?

As our daily lives speed ever faster, it may be useful to pause – got time to? – and reflect on how the fleeting ant-like lives of humans fit into the scale of Real Time – that of the Ages. So incomprehensible is Earth time compared to our own span that geologists have playfully tried to bring this time into focus – sort of:

If all of Phanerozoic ("visible life") some 570 million years long were squeezed into one of our years then animals with backbones (chordates) would slither onto land for the first time in mid-April; dinosaurs appear in early July but die out in late October and humans appear on earth about 2 hours before midnight on New Year’s Eve.

So – what’s the hurry?

Most of us have come to think of shoddy metal-ware as "tinny", inferior, even junky. Tin can. Tin Lizzy. Probably because of the use of tinplate where more solid steel was required. But oldsters will recall that the dear departed "Tin Lizzy" was the affectionate sobriquet hung on the Model T Ford, the car that put the world on wheels.

Cassiterite is usually brown to black – but even yellow and white – grains and holds about 78% tin.

Considering its scarcity, it is surprising to learn that tin was combined with copper (Cu) as early as 3000 BC in SE Europe, thus founding the Bronze Age. Was bronze an accident of smelting tin and copper ores together? In those days tin was found in Portugal, Scandinavia and Bohemia where it was near copper ores. Control of metals meant power and wealth. (Shades of the oil business today?)

Later tin was mined in Cornwall England to depths of 100m and became a major trade good.

The bronzes of ancient Ur contain only 10 to 15 percent tin, indicating that a small amount has a large effect on alloys. This is fortunate because of its scarcity.

Tin as metal is silvery white, soft and pliable, melts at a reasonable 232° C but has an astonishing boiling point of 2625° C, the highest except for platinum (Pt) and tungsten (WO).

Tin has the knack of "wetting" other metals as iron and copper and so can carry metals as lead and give smooth flow to solder (also known by the Ancients) and the shiny film on sheet iron, its greatest use. Next stop – tin cans for food because tin isolates the effects of iron on food.

Other uses beside tin plate? Its in bronze for bells (no connection with tinnitus, ringing in the ears!). But off-key singers in the choir may have "tin ears" for music. Tin is the metal of choice for organ pipes. Then there is solder, babbitt metal for bearings, white metal and pewter and before-plastic-age in toothpaste tubes and – open wide please! – dental fillings (12%).

Our gem polishers may use tin oxide powder to polish stones and scientists believe tin and niobium may have uses in superconductors. With zirconium, tin finds use in nuclear reactors.

Like OPEC, the price and amount of tin on the market is tightly controlled by the International Tin Council operating mostly out of Penang and London. The price is about $15 to $20 per kg. Hardly a free market! The U.S. stockpiles about 200,000 metric tons, a recognition of tin’s importance.

But a tin compound has reached notoriety status recently. Tributyl tin used to paint ships’ hulls has been found highly toxic to marine life – its purpose of course, as anti-fouling coating – and because these ships also sail our Great Lakes, tributyl tin has been found in lake waters and fish. Whereas a ship must usually be dry-docked every three years to be scraped and painted to remove speed-inhibiting barnacles and weeds, painted with tributyl tin compounds, that job is stretched to seven years, a great saving in money, in speed and time.

In this case tributyl and similar tin compounds are to be banned worldwide by 2005.

Not a bad history for a little known metal.

We members of our Brampton Club should occasionally remind ourselves that we have rock as well as mineral interests. And so, always in the superior judgement of our editors, this space would like to offer some – hopefully – interesting information on this literal foundation of geology – rocks.

Even among elementary school children Granite is the most correctly identified favorite. For that matter it is also for adults. The reason is more or less obvious – it’s usually spotted with large "grains", hence the name.

There is a vast literature and equally vast disagreement about granite, centering mostly on its origin. It certainly is "plutonic" – its large crystals attesting to deep slow cooling in the crust. But does it come from recycled sediments of uncertain source or metamorphic material or has it crystallized from certain kinds of magmas? The dispute rages, but with our better understanding of crustal-plate movement many scientists favor the idea that as the continents drift across ocean floors, the thick deep-sea sediments are scraped off and forced under the continents to great melting depths.

It’s suggested that this now-buoyant liquid (magma) or mush begins to rise as great balloons – remember the once-fashionable lava lamps? – melting and/or displacing overlying country rock as they head toward the surface of the crust. It appears significant that these great bodies of granite – batholiths – are found under mountain ranges. There, hoisted by mountain building (orogenesis) the overlying rocks are often removed, exposing these granite masses to view. For example we have the Nevada, Idaho, Nelson and Coast Range batholiths (deep-rocks) beautifully available for our inspection. Well, sort of. While surface exposures may be hundreds of kilometers wide by thousands long parallel to the Coast Ranges, there is no way of knowing how deeply they extend, their uniformity with depth or the mechanics of their formation. No technology in sight will be of use.

Even the definition of granite has been hugely corrupted, mostly by the building-stone industry where almost any rock with visible crystals may get plugged into the term. Presently true granite is made up something like this "rubbery" analysis: quartz 20 – 60 %; feldspar(s) 30 – 70 % and dark (mafic) minerals as biotite and horneblende in small amounts. Granite forms the cores of all continents because its SG of about 2.7 allows it to "float" on the heavier – SG 3.3 – basalt of the mantle. It’s also lighter in color thanks to quartz and feldspars.

The sloppy definition of granite is largely due to the kinds and quantities of feldspars present. If you can hang in there long enough we’ll try to sort out the feldspar mess another time.

Uses? Well, if we’ve lived the good life, perhaps caring survivors will plant a plain block or a handsomely carved monument over our bones – tombstones. A more conspicuous use is as facing on (bank!) towers and commercial buildings.

Have you ever walked or cycled over old European streets? "Belgian blocks". We may suspect that these were laboriously hacked into shape in prison quarries.

For reasons to be explained, this series of minerals has spawned a vast literature. But happily for most of us, the essentials can be sifted rather easily.

The way the books often present the subject is with a triangle. So let’s try that. At the top we may visualize potassium (K, for kalium, the original name); at the lower left-hand corner we’ll put Na (for sodium) and at the right hand corner put Ca, for calcium.

Further confusion is injected by the effects of pressure and temperature of formation which changes the crystal structure, though a lump of say the potassium feldspar orthoclase may look like a lump of the potassium feldspar microcline.

But have heart, dear readers, all is not obfuscation (?).

The series Ab to An has been arbitrarily sectioned off into six handy blocks depending on the Na (Ab) to Ca (An) content. Ready? – albite, oligoclase, andesine, labradorite, bytownite and anorthite. Ab used here stands for albite, a white feldspar rich in sodium (Na). An is used to represent the calcium-rich feldspar called anorthite, dark gray to black.

How to tell them? Tough in the field but generally a clue is color; the more Na (Ab) the lighter the color; the more Ca (An), the darker. And one, labradorite is famous as building stone for its silky blue sheen in a gray mass.

Potassium feldspars – orthoclase and microcline – are generally flesh-to-salmon pink, have very good cleavage and, if green, the microcline kind makes a nice gemstone as amazonite.

As for those "big six" above, they are lumped together as plagioclases. So you see there is a way out of this mess!

Uses? Not many considering their abundances. Mostly microcline and orthoclase are used in ceramic glazes and mild abrasives in cleaners (H6 on Mohs scale). Kaolin, a valuable white clay may form when feldspars decay and most soil clays owe their origin to feldspars.

Now the good news.

The test announced for tomorrow on feldspars has been cancelled indefinitely. Life is not all gloom!

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This contradiction is not apparent because both of these minerals are rose-red. We mean of course rhodochrosite and rhodonite. Lapidaries quickly learn the difference as soon as they start to work these minerals because, while they look alike, rhodonite has a hardness of 5.5 to 6.5 – about as hard as a feldspar – while its color-twin rhodochrosite has a hardness of 3.5 to 4 on Mohs’ scale.

Rhodochrosite is often found with galena (lead), sphalerite (zinc), chalcocite (copper) and bornite (copper). While not the richest in manganese (Mn), at about 48%, it is a useful source of that metal, a vital component of steel. Where? Germany, Cornwall, Butte etc.

But it is a favorite of cutters and shapers for beads and ornaments. Where? Franklin N.J., Urals in Russia.

Now can you tell them apart?

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Its greatest use is in nuclear reactors as a moderator and reflector; in beryllium-bronze moulds for plastic; in sheet and foil for "windows" in x-ray tubes, electrical porcelains and aircraft spark plugs. Alloy tools are used in explosive situations such as oil refineries, precision instruments, computers and camera shutters.

Beryl is the only source of the metal and while gem quality may be rarer, beryl is widely scattered in granite-related rocks from all continents. The gems are usually found in pegmatites, veins and sometimes in rhyolites (think fine-grained granites). Emerald occurs in mica schists in Egypt, Austria, the Urals and North Carolina, but the most famous deposits are in albite (white feldspar) quartz veins in bituminous (oily!) limestone in Columbia.

Rare beryl crystals to 3m long and several tonnes are known. Commercially beryl crystals are hand picked from the ore, 90 tonnes yielding about 0.5 to 1 tonne of beryl. Industry uses about 3600 to 9000 tonnes a year, reflecting highly variable production. Mozambique and Brazil are the main sources.

A good emerald rates close to a diamond in value, so if you happen to be in
Columbia....

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In an earlier article we read about the wonder and mystery of granite. Here we consider a rock of opposite composition and behavior, basalt. While the technical literature mentions 400 kinds of rock of all kinds, granite and basalt are the two of major importance. The reason? Granite forms the cores of all the continents "floating" as it does on denser basalt and similar rocks which constitute the bulk of the earth.

These dark and – for rock – heavy (SG 3.4) rocks are rich in iron and magnesium for which we coin the term mafic and even ultramafic for exceptionally heavy types. So really basalt is just a representative of a family of dark and heavy rocks. But because there are vast amounts of it visible at the surface, it is the best known of the class.

What characterizes basalt? Certainly abundance. It has little or no quartz. This greatly reduces its melting point (1200° Celsius) and the result is a highly mobile lava which allows spectacular fiery fountains and liquid streams down the sides of volcanoes. Hawaii and hundreds of oceanic islands are typical. Gases escape readily. In contrast, quartz-rich lavas as in Mt. St. Helen’s are very viscous at that temperature, gases are bottled up until only an explosion relieves the pressure. Disaster. That is why "tame" basaltic volcanoes are the most studied.

The bulk of our earth beneath the continents is of basalt and similar rocks so it’s no surprise to see a few "leaks" onto the surface. Witness the thousands of square kilometres and immense thickness of the Columbia flows in NW States, the vast Karoo fields of Africa and the Deccan Traps of India. Since no volcanic cones are known, the flows apparently oozed from huge gashes – now buried – in the crust. A visit to Spokane and the Columbia River country is a worthwhile trip.

While basalt at the surface is not the most common rock in our reachable area of the Shield – granitic rocks are – there are dikes cutting granites in many places. Try north of Kingston, along the Frontenac Arch, but don’t expect a treasury of collectables in basalt. Bubble holes may now offer us calcite, chalcedony, native copper, prehnite and zeolites.

Don’t write basalt off though! Spectacular scenery – Ireland’s Devil’s Causeway, Wyoming’s Devil’s Postpile for starters (why always the Devil?!) Weathered basalt sands may release the beautiful yellow – green olivine called peridot. But for real heavy – duty collecting seek out basalt’s rare ultra – basic cousin, kimberlite – wouldn’t a diamond fit nicely into your collection?

And there’s a great bonus for mankind – decayed basalt makes very fertile soil, baiting farmers ever farther up to the dangerous vents.

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As collectors of minerals, one of the most sought–after specimens on trips to mine dumps is surely fine galena cubes. Although galena may show up in several other forms, the isometric cubic habit is the most cherished, with sides up to eight and ten centimetres. Seldom a single trophy, the brilliant cubes are usually twinned into clusters, making for a great cabinet display.

Galena (PbS) is the most common ore of the metal, with 87 percent lead and 13 percent sulfur, but it is usually host to valuable amounts of sulfur and gold as well as possible selenium, zinc, cadmium, antimony and copper sulfides. It is frequently found with zinc (sphalerite ZnS) and silver ores. One book lists over 150 other minerals containing lead.

The symbol Pb stands for plumbum, the Latin name for lead, so it was logical at the time to call those who worked with it "plumbers". And so it is. Field tests, aside from the nice cubic habitat are: H 2.5 (soft) and SG 7.6 (heavy) and a grey streak on test tiles. It’s one of the most widely distributed of the metallic sulfides and, not surprisingly, a good candidate for ancient "metallurgists". Lead relics predate Egyptian times and the role of lead in Roman history is legendary, from lead utensils (wine goblets!) to lead pipes. It’s reckoned that any resourceful civilization would – sooner or later – learn that a fire next to a suitable outcrop would liquefy galena to the metal. Modern metallurgy has learned to handle the more common, complex ores.

Lead has many uses both modern and ancient. Roman pipes still pour water into the baths at, yes, Bath, England.

Sheet lead was widely used (still is) for Church roofing in the Middle Ages where it had another handy use – melted and poured onto attacking invaders it must have been a spectacular deterrent.

These days we no longer pour it onto heads but into things like battery plates – the largest user by far – solder, type metal, low-fusing alloys with bismuth and tin, engine bearings, pigments (but not in household paints), as azide in detonators and shielding (as glass) in x-ray rooms and around atomic reactors. And for fun make a simple radio receiver using a galena crystal. Parts should be found at radio supply shops.

We are now more sensitive to dangers in many ways and lead compounds are high on the list. It has serious consequences to the brain especially in children. Tetraethyl of lead for decades put in gasoline to reduce engine knock is gone. It’s no longer in domestic paints or glaze on pottery. Even the solder (lead and tin alloy) used with copper piping is suspect. Lead shot kills birds which ingest it instead of natural grit for the gizzards. The sweetish taste of lead paint tempted children to nibble peeling bits. It’s now known that the ill-fated Franklin Arctic expedition of 1845 may have been handicapped from lead poisoning from soldered food tins.

These depressing observations indicate not only the hazards but how ubiquitous is this valuable metal in our society.

And, despite the joke, dear readers, lead is not used to make balloons!

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Author of several monumental works, mostly on mining and mineralogy, he is best known for De Re Metallica possibly because it was exhaustively translated from Latin by Herbert (later President during the great depression) Hoover and wife Lou. This made it widely available. Hoover was a mining engineer and appreciated Agricola’s treasure trove. First printed in 1556, De Re Metallica was so thorough, complete and – for the times – accurate that it became the standard textbook for over 180 years, surely a record!

Agricola, also a physician, settled in Zwichau in 1527 and soon became dazzled by the booming mines – sound familiar? –at Freiberg and area, some 75 km away. Here he spent all his spare time in mines and smelters, reading Greek and Latin authors on the subjects. He used color, hardness, solubility and other available properties to classify minerals. He added about 20 new species to the minerals (some 60) already known. As mankind has before and since, he dwells at length on the processing of gold and silver though copper, iron, tin, bismuth, mercury and lead are regarded highly.

The Hoovers went to great pains to retain the original "flavour" of Agricola’s work, written (as was the custom) in Latin, despite the numerous German and well as ancient and Greek terms. It is truly a monumental example of scholarship.

Agricola wrote it in 12 "volumes" which, in modern parlance would be considered chapters. The language is clear and precise though repetitions make for tedious reading. But an outstanding beauty of the book it is over 280 excellent woodcuts by an unknown carver, showing in exquisite detail mining and processing of the 1500’s and into the 1700’s. In many cases one need only add steam, diesel or electric power to his apparatus to update his (and his contemporaries’) designs.

Here is a copy of a picture, in the case showing a man–powered windless for hoisting our buckets from a mine.

De Re Metallica is a long, fascinating, sometimes tedious read, hard to come-by (mine was borrowed from Hamilton’s Library), but absolutely worth it.

As Agricola himself would probably say – It’s a gold mine!

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In these times of superb – and expensive – devices for peering into the inner secrets of minerals and even their atoms, it may be instructive to see how far we’ve come in mineral identification. For many years x-ray has been a valuable tool but before that. What?

Here is the taste – yes, that too! – of what a geologist faced in a typical mineral lab, taken from an old text book and abridged here:

The use of the blowpipe in skilled hands gives a quick method of obtaining partial knowledge of the qualitative composition of a mineral.

Apparatus – blowpipe, lamp, forceps, preferably with platinum tips, platinum wire, charcoal, glass tubes, small hammer, steel anvil, magnet, agate mortar, cutting pliers, three-cornered file; test paper (turmeric and blue litmus paper), some pure tin foil.

Then there are fluxes in small wooden boxes – borax (sodium tetraborate), soda (sodium carbonate), salt of phosphorus, potassium sulphate, some cobalt nitrate solution and hydrochloric, nitric and sulphuric acids, ammonium hydroxide etc. etc, finally distilled water.

And there is more but you get the idea.

Long ago in a far away land, a hungry creature hurled a handy rock at a paleo-rabbit and so finally got a meal. Next day this same "lucky" stone felled a bison and the whole tribe ate well. Would you cast away such a valuable article?

Well, perhaps rock collecting didn’t get started this way, but somehow the idea stuck and mankind has been clutching pretty stones and minerals ever since. Along with this hankering came the human urge to classify them and mineralogy, the science was born.

The most influential "father" was certainly James Dwight Dana, born in Utica, New York in 1813. His "System of Mineralogy" appeared in 1837 and has been revised by numerous authors since. It is still the mainstay in any library on the subject.

Dana was no book-bound academic. In those days cadets for the navy were taught at sea and, through the efforts of a professor Silliman (of sillimanite fame) the young Dana shipped out, first to the Mediterranean as the math teacher. Trips to Brazil, Chile, Hawaii (then called the Sandwich Islands), Australia and New Zealand and around the world to New York followed.

His fame originally came, not from minerals, but from his work on corals and geology. His earlier System preserved the Latin Binomials as still used in biology but in the third edition he used only the chemical classification which we know today.

Between these editions came the "Manual of Mineralogy" which dealt with rocks, ores, mining and the use of minerals in industry. For years Dana taught at Yale, an inspiring and thorough instructor willing to take correction for wrong ideas. He was a great believer in field trips, by foot and by rail. Regarded as a great thinker and great man, Dana died aged 82, in April 1895.

Those of us interested in minerals now accept "some kind of system" – it’s Dana’s. Few, we suspect, can rattle off the classes of minerals but this is the way Dana devised it: natural elements, sulphides etc., chlorides etc., oxides, carbonates, silicates…well, you get the idea.

Thank you, James Dwight Dana.

This portrait of James Dwight Dana (1813-1895) was done in the 1920s by Abner Lowe.

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The word means "joined together", first applied in 1822 to describe graphic

granite, an uncommon form which looks like some primitive "writing." Now the term includes any coarse-grained igneous rock. We usually mean granite pegmatite but in fact pegmatites may be formed in many kinds of igneous rock, even basalts. So don’t ignore any igneous masses when searching for specimens.

Grains in pegmatites vary widely in size from centimetres to metres. Giants

Simple pegmatites are rather homogeneous, with mostly microcline feldspar and quartz with a little biotite (black) mica and black tourmaline. But complex pegmatite’s – the kind collectors love – have besides various feldspar, goodies to warm the heart – large crystals of muscovite (clear mica), beryl (emerald, aquamarine, morganite, etc.), topaz, coloured tourmaline and spodumene. Much rarer ones too, like lithium, niobium, tantalum, cesium, uranium and the so-called rare earths. Treasure indeed!

Simple pegmatites usually occur as dikes – near-vertical injections cutting

country rock. They are rather common in our Shield rocks. But "good" ones occur as pods or irregular bodies within the country rock surrounding large igneous masses, or seemingly with metamorphic bodies.

Origin? Uncertain. Most pegmatites form from late stage liquids "squeezed" out of cooling magmas.

As collectors, most of us settle for "thumb-nails" or micro-sizes of specimens, so lucky indeed is the bushwhacking collector who stumbles onto such a pegmatite where rare giant treasures of museum quality may lurk.

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While De Beers may vigorously extol the virtues of diamonds as girls’ best friend, few voices extol the virtues of humble talc as everyone’s best friend. Ever heard of diamonds easing diaper rash?

As it sprinkles out of the can talc hardly behaves like a rock or a mineral with its silky smoothness. At H1 on Mohs scale and perfect basal cleavage these tiny flakes of mineral are familiar to all of us.

When more or less pure, talc is considered to be, well, talc. In massive form and colored apple green to brown–black–green it’s usually called soapstone or steatite. Useful deposits may be scarce but it’s really rather a common mineral, the alteration product of often dolomite but also ultra-basic or mafic minerals as olivine, (peridot to gem collectors) serpentine, asbestos, actinolite, tourmaline and magnetite all associated with so-called mafic minerals – those rich in iron (Fe) and magnesium (Mg) and low in aluminum (Al) and silicon (Si). Its structure seems unable to accept Fe or Al, as in chlorite, resulting in a constant pure composition. Oddly, talc and steatite are seldom found together. Pyrophyllite, an aluminum silicate i.e. not magnesium, is often used as a substitute for tale.

In summary, talc is light to white, very greasy to the feel, H1 and SG 2.7.

Soapstone (steatite) is massive i.e. in relatively large deposits, impure, coarse to fine texture, gray to greenish, H1.5 and SG 2.5.

Long a favorite of sculptors, ancient to modern, the soft stone is easily worked with simple tools. But it also has many industrial uses. Some of them: toilet powders (see, I told you!) soaps, leather dressing, waterproof cement, ceramics, dry lubricant e.g. in car door locks, filler in paint, paper, rubber, roofing and insecticides. It marks iron, glass, fabric and – if you are old enough to remember! – pencils used on our school slates.

According to our esteemed former president, Court Saunders, who knows just about every gopher hole and mine over a vast area, Madoc Ontario is one place with significant deposits of steatite in Canada. Another is Broughton, Quebec. This is a major source of soapstone air-lifted to the far Arctic for the Inuit craftspeople, closer sources (Devon Island?) having been exhausted.

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Some of our collectors can spot the difference immediately. Can you? Here is what to look for.

First, concretions. These are aggregates in sediments of inorganic matter in many but usually spherical or discoidal shapes. Often there is a nucleus of some sort – a bit of pyrite. A tiny fossil remnant, a shark’s tooth – but it may be absent or microscopic.

The origin of concretions is controversial; see what you think after you’ve read the rest of this story.

They are commonly composed of one material but others may be present as impurities. These are some likely contenders; calcite (the most common), silica, hematite, siderite and other iron compounds; gypsum, barite, aragonite (cousin to calcite), manganese oxide, calcium phosphate, fluorite and bauxite (the ore of aluminum).

Calcite is the chief material in claystone and calcareous concretions so common in shale and sandstones.

Siliceous concretions usually are nearly pure silica, as in chert and flint. Commonly scattered throughout chalk beds these often contain the tiny remains of radiolarians (siliceous foram inifera) and sponge spicules (skeletons).

Siderite concretions (iron carbonate) may be so abundant as to form (low-grade) iron ores. Pyrite and marcasite concretions (iron sulfides) are widespread in shale, limestone and especially dark marine shales. Barite "roses" are usually products of desert sands. Calcium phosphate nodules are valuable sources of that mineral.

Other concretionary shapes are due to other processes – oolites – like fish-eggs – is the common form for bauxite, the ore of aluminum. Then there are larger pea-sized forms – pisolites, rolled about in shallow warm seas.

Sizes? How about log-shaped forms to 10 m? These usually form in sandstone.

Origins? What causes minerals to migrate to a center and become harder i.e. a strange foreign shape, in a sedimentary bed? Some are revealed only when they weather out of an outcrop. How come the fine bedding planes of the host rock continue right through the concretion?

Septarian nodules (from Latin septum = partition) are marked by a network of cracks usually filled with calcite.

The prizes for collectors of concretions are the hollow types called geodes. These globular types vary from centimetres to about 30 centimetres and usually have a rough surface of dense chalcedony. They are typical of some limestone beds but seldom in shales.

What intrigues collectors is the possibility of a geode to contain spectacular crystal growths. But because geodes, once released from their enclosing beds tend to look like ordinary boulders they must be broken open to reveal any treasure. And guessing which "boulder" to smash open – and possibly destroying the interior – is a problem facing the finder. Estimating weight may be of some use. Random sawing is time consuming.

It’s difficult to imagine the lowly concretion being involved in deep intrigue – literally. In the dark days of the Cold War, the Hughes Company was commissioned to design, build and operate an immense floating "mining machine" to allegedly recover from the deep Pacific sea-floor the millions of manganese nodules known to form there. They did.

Only years later did the public learn that this was in fact a CIA secret operation to recover a sunken Russian submarine. Nearly at the surface, the apparatus failed and the hulk sank again among the nodules.

The cause of geodes and concretions and various modular objects make interesting but lengthy and erudite reading for those interested.

But this isn’t necessary to enjoy the wonder and often the beauty of these strange objects.

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This domestic order may be mythical, but not so the shard on which it may have been written - clay. It’s not likely that one of our lists will be available to archeologists after 5000 years like these were.

Perhaps the ancient writer and his "grocery store" also were sheltered by sun-baked bricks - of clay.

No other earth material has so wide an importance or such extended uses, as do clays. By far the greatest of these is in soils, a storehouse of chemical fertility which, through vegetation, is a hinge-pin to the survival of life on earth.

The Sumerians didn’t have polarizing microscopes or X-rays to study the nature of clays which today tax our technology. The major problem is the extremely small size (0.004mm), demanding even electron microscopes.

Clays all have sheet-like structure, like mica, and all are aluminum silicates. It’s this structure and which ions come and go between these sheets, which accounts for their strange and versatile behaviour. Some are slippery when wet, some exchange, say, calcium (Ca) for sodium (Na) to give us water softeners. Some fuse when hard - baked to give a bewildering variety of ceramics and bricks.

A complicated variety can be grouped thus: Kaolinite, white, grainy, fires into fine porcelains, fire brick, paper coatings and even goes into our tires. Wales is famous for its kaolin pits.

Then there is montmorillonite or bentonite or smectite derived from volcanic ash. It absorbs a huge amount of water to become creamy and slippery. Ever been stuck in "gumbo"? Then you’ve met this clay. It has a great commercial use in oil-well drilling muds where it keeps gas pockets suppressed, lubricates the drill bit and brings cuttings to the surface. After certain treatments it becomes an excellent agent for clarifying oils and other liquids.

The third group is less specific and less useful though it forms a large part of the soils.

So we see that what goes on between the sheets in clay also rouses our interest! The term "dirt" may be a put-down, but who is going to argue when we see a fine crop of grain or corn?

So - that’s the "dirt" on clays.

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Si stands for silicon, and though it’s the second most abundant element in the earth’s crust, we didn’t hear much about it - until Silicon Valley put it on the map. It is present in measurable amounts in nearly every rock, in all natural waters, as dust in the air, in the skeletons of many plants and some animals, even in the stars. How come we don't hear more about it then?

For one thing, silicon is never found in the free, i.e. native, state like, say, gold or silver, but is always tied up with oxygen (O), aluminum (Al), magnesium (Mg), calcium (Ca), sodium (Na), potassium (K), iron (Fe) and other elements in bewildering combinations called the silicates. This is the largest and most complicated of all our rock forming minerals.

Its Latin root refers to flint; it has the same structure as diamond yet for a long time was considered amorphorous (non-crystalline). It is dull gray, sub-metallic in appearance and has SG of 2.42, that is, lightweight. But it has loose electrons like carbon (C) and so lends itself to a vast array of chemical compounds like silicon carbide abrasive, silicon rubber and caulking, oils and paints. And two of the most dramatic uses of pure silicon is in semiconductors, opening the floodgates for such marvels as solar panels to generate electricity from light and microchips for transistors.

And we all know where that leads us - computers.

Oh, and about that little bit of oxygen? .... Next time.

Silica is a compound of the two most abundant elements in the earth’s crust, oxygen and silicon. It is the main constituent of more than 95% of the earth’s rocks. It is highly resistant chemically and so survives to concentrate in loose sands and in tough quartzite rock. Technically sand is a grain size (2mm to 1/16mm on Wentworth’s scale) but we can safely regard most sands as made of quartz.

Though highly stable, at high heat it can be coaxed into several forms, the three principal ones being quartz, tridimite, and cristobalite. Certain forms expand very little and products can be plunged red-hot into cold water without cracking. Don’t try that with your coffeemaker, but you get the idea.

Quartz is H7 on Mohs standard, SG 2.65 and has no cleavage. In fact, its break result in well known barbarous shards, for good and bad. Fine hexagonal crystals are common.

And it’s the darling of lapidaries because - ready?... Macro crystalline (big) quartz includes amethyst, aventurine, rock crystal, citrine, prase, hawk’s eye, cat’s eye, smoky quartz, rose quartz, and tiger’s eye. Fine or micro-cystalline forms include chalcedony, agate, fossilized wood, chrysoprase, heliotrope, jasper, carnelian, moss agate, onyx and sard.

Amorphous quartz (without form) includes the opal group - precious, fine and common.

This common, versatile mineral has vast industrial talents too. While it is a non-conductor of electricity (and a poor one of heat) it is piezoelectric and generates charges on prism edges under pressure or tension. It will also in turn vibrate when subjected to alternating charges. But don’t expect your cherished "Herkimer diamond" to dance its way out of your cabinet - this effect applies only to precisely cut pure quartz. Quartz watches prove it can be done!

Our fur-skin-clad ancestors hand us down a few tips on the "industrial" use of some forms of quartz. Hard, tough shards were great for doing in mastodons and dire wolves for tribal banquets. And quite some time later we used bits of flint to fire off our muskets - and thus do ourselves in!

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… that depends on the compound, the use and the concentration. This unusual element sits on the fence between metal and non-metal. Chemists consider it the latter because of its properties which permit a host of compounds, good and not so good.

In its metallic form and extremely pure – 99.999% - arsenic is used to "dope" solid-state devices of various kinds, often combined with the element gallium as GaAs, and in lasers. But far larger amounts are used in a host of compounds. Most of these are highly toxic and some find their way into insecticides and weed-killers though they are being displaced by newer organic compounds.

But arsenic has some good sides too. Its compounds decolorize glass and preserves wood. In metallurgy it appears in copper alloys in car radiators to resist corrosion. It is added to lead to make rounder shot pellets. Bearings are made more heat tolerant with a little arsenic added to the lead – tin – antimony mix. And some arsenic hardens the lead in storage battery plates.

Although it is sometimes found native, this semi-metal is usually combined with bismuth, cobalt, nickel, silver, iron and gold. Most commercial production comes from smelter flue dust which is then re-roasted to condense out crude white arsenic. This is then refined into purer form.

But in general arsenic is regarded as a dangerous nuisance to smelters.

Arsenic has several valences, a measure of its ability to form many compounds from wood preservatives to deadly arsine gas.

When poking around mine dumps – fossicking in Australia – the most likely mineral we may encounter of the arsenic family – there are over a dozen members – is arsenopyrite or mispickel. It has a distinctive silver color, tarnishing to brass-yellow, H 5.5 – 6, S.G. 6 and the crystals sport fine striations. On the streak-plate it marks black.

Because many ores contain arsenic, it’s hardly surprising that it shows up in mine waters and leaches out in dangerous amounts from finely ground tailings of numerous mine dumps into ground and surface water.

Residents of Yellowknife and many native communities near mine sites are increasingly worried about arsenic-contaminated drinking and fishing waters.

And what’s this talk about arsenic being found in analyses of Napoleon’s hair? Yes, he of Waterloo. Exiled to a volcanic dot in the south Atlantic – St. Helena – was he done in with arsenic in 1821?

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Some names for minerals have been with us since ancient times. If we are boggled at the vocabulary of some 3000 valid names, how can we hope to handle nearly 20,000 names which occur in the literature? This confounding situation arises because various workers have given names to minerals, also dubbed by others. Or later research has proved the similarities of varieties or mixtures. Newer instruments also permit keener analysis.

Some are named after Canadian places like bytownite (old Ottawa, a feldspar) and hilairite (St. Hilaire quarry). There are about 80 of these alone.

Some names may indicate composition as caysichite (Ca, Y, Si, C, H) found in Quebec. Others are named after people who were instrumental in analyzing them – steacyite after a Canadian mineralogist. Or areas, like sudburyite, cobaltite, labradorite (a feldspar).

The suffix "ite" is derived from the Greek word "lithos" for rock or stone and defines most minerals but we also have "ine" and "ide".

And this naming game works backward too. For rivers, hills and islands etc., don’t we have agate, calcite, copper, amethyst, gold jasper, ruby, sulphide, topaz and zircon?

How many more can you spot on Canada’s map?

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Why not? The earth is conspicuous among planets by having water, lots of it. It’s obvious our lives depend on it, but so do numerous natural processes in the mineral world and a large category of our metallic and non-metallic ores are classified as hydrothermal – hot water – in origin. Pure water functions as a standard for some of our measuring units because of its uniformity.

Above 0’ C it is a liquid hence amorphous (without form). Pure water has a bluish color. Its specific gravity (SG) when pure, at 4’C and 760mm barometric pressure is 1, though seawater may be up to 1.028.

Nearly all minerals are more or less soluble in water, especially if it contains carbon dioxide, humic acid, hydrochloric acid or oxygen. There is about 3.5% solid matter dissolved in seawater, which contains over 30 elements in solution. Molecules of water aid in the migration of ions to form new "metamorphic" minerals like garnets.

When it freezes it expands by about 9 to 10 percent and exerts tonnes of pressure per square centimeter, widening cracks in rocks and hastening the activity of water and oxygen in weathering and disintegration. Cold water holds a lot of calcium carbonate – the stuff that shells and corals are made of – but when the water warms, this calcite crystallizes out to give vast deposits of limestone.

When it freezes in the air, snow crystals are formed – all different we’re told – tabular and hexagonal.

And is there anything better for taking licorice and jam from little mouths and fingers?

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The name of this gem – at the tail end of the (our) alphabet – traveled all the way via Greek for "hyacinth" to the Persian word "Zargun", hence "zircon". The name is embedded in that of the element zirconium.

Despite man’s historical cupidity over the ages, the real value of this substance is not as decorative gemstone but as the element zirconium. The natural compound is ZrSiO4 containing 33% Silicon and 67% Zirconium, making these crystals a valuable source of metal.

Zirconium is a silvery metal which stays shiny because of an oxide on the surface. It conducts electricity poorly compared to copper, and while non-reactive in larger pieces, may ignite spontaneously when finely divided.

Zircon is the most important ore and is panned in placer deposits as stream and beach sands although it’s widely distributed in acid (i.e. granite-type) rocks, usually as a fine accessory mineral. But in pegmatites – veins of especially coarse crystals – zircon grows to more "useful" sizes.

The metal itself has many modern industrial uses, especially in the nuclear industry alloyed with tin (Sn) iron, nickel and chromium. It may be found in military flares, detonators, brazing metal to ceramics foam aluminum, and refractories. Zirconium boride, carbide, and nitride are extremely hard. Also in ceramics, glazes, enamels, foundry molds, uranium fuel cladding, water-repellant clothing, paint dryers, tanning ion exchangers, deodorants & antidotes for poison ivy.

But we aren’t finished yet. When zircon crystals form from a magma, they incorporate a tiny amount of uranium and/or thorium. As these radioactive elements decay to form lead at a known rate, a time (years) of formation can be calculated, when that crystal "froze" i.e. the date of the rock.

Thus the age of the granite in Sri Lanka whence comes a good supply, is dated at about 550 m.y. (million years)

More surprises: it turns out that northern Canada hosts the world’s oldest rocks (so far). The date – 403 billion years, the rock is the Acasta Gneiss northwest of Yellowknife.

There are scores of minerals which resemble diamond, at least superficially. As seen on TV, jewelry featuring cubic zirconium and diamonelle are an attempt to capitalize on diamond’s brilliance and fire. A quick tally in books reveals hardly a gem which cannot be manipulated to imitate color especially, hence value. Radiation, heat with pressure, heat without pressure, immersion in various chemicals, molten processes or immersion processes, any or all may be successfully used to make a stone more saleable.

Although there is plenty of scope for a scam for the unsophisticated buyer – aren’t most of us? Many of these various procedures were done to make the materials more versatile to industry. Me? I’ll take that poison ivy item!

But – caveat emptor!

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Can you think of a mineral treasured by collectors, which is a mixture of copper, aluminum with water and is classed as a phosphate? And it’s blue too?

Venture turquoise, and you will be right. This gemstone has all the merits demanded by lapidaries – a hardness for durability, H 5-6, beauty when polished and no menacing cleavage.

While the most valued color is a delicate sky-blue, it also comes in green, green-gray to yellow-gray. It’s opaque and takes a good waxy polish. Some more porous varieties may become greenish and grayish in the presence of heat, sunlight and perspiration, even losing its color.

Turquoise is a secondary mineral often associated with limonite (iron oxide), quartz, feldspar or kaolin (clay). It usually occurs in dense cryptocrystalline nodules and crust, sometimes in small seam. It’s found chiefly in arid regions usually in fractured volcanic and sedimentary rock. The stone has been highly valued for thousands of years. As early as 3400 B.C. it was obtained from Egypt’s Sinai Peninsula in perhaps the world’s first hard-rock mining venture. It was also mined in Iran, which reached Europe via Turkey whence may have come its name.

Because the stone is so porous the color can be improved with dyes and copper salts. And – caveat! – it can be faked! Chalcedony and howlite may be dyed and passed off as turquoise.

One of the nearest and best sources is New Mexico and other localities in the desert of the Southwest.

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Because it floats, sepiolite is also known as meerschaum or sea foam. Most of us do not file this mineral in our lexicon probably because we encounter it so rarely. The proper name is sepiolite and refers to its similarity to – via Greek – cuttlefish with its light and porous bone. A piece could be fixed in the wires of your canary cage to help birdie sharpen its bill.

Most sepiolite comes from Turkey where it occurs as scattered nodules egg to football size, but some has come from New Mexico, Greece, Monrovia; sparsely in all places.

Its principal use is in smoking pipes and cigar holders, the craft beginning in Budapest in 1723. It was the first pipe to challenge the clay pipe, which had been around since 1575. With use these pipes acquire a rich golden sheen, much cherished by aficionados, and demand a high price. Both the pipes and cigar holders are usually fitted with a more durable mouthpiece of amber, further increasing their value.

Briar root today provides the bulk of good pipe material. It resists burning and absorption of tobacco tar or "heel". But meerschaum – sepiolite – is still the most cherished material for puffing the weed.