All rocks are made of 2 or more minerals, but minerals are not made of rocks.

Rock Words: There are many common names for rocks and the usually give you an idea of how big the rock is. Here are a few:

	mountain - huge, giant hunk of rock that is still attached to the earth's crust, doesn't move, tall
	boulder - large, taller than a person
	rock - large, you could get your arms around it or a bit smaller but it is usually jagged, broken off a bigger piece of rock
	river rock - round rocks that are along the edge & at the bottom of fast-flowing rivers
	stone - medium, you could hold it in two hands
	pebble - small, you can hold it with two fingers, could get stuck in your shoe, usually rounded
	sand - made up of tiny pieces of rock, grains of sand
	grain - tiny, like a grain of rice or smaller, often found on a beach
	dust - really fine powder that is mixed in with sand or soil
	speck - as in a speck of dirt

For an excellent Rock Identification Test, click on http://www.bwctc.northants.sch.uk/html/projects/science/ks34/rocks/key.html

	A mineral is the same all the way through. That is one reason we speak of a sample or a specimen rather than a rock.
	There are about 3000 known minerals on earth.
	All rocks are made up of 2 or more of these minerals.

For a good explanation of the difference between rocks & minerals, check out http://www.rocks-and-minerals.com/

Most rockhounds start out by just looking at rocks and getting to know them. But after a while, you're going to want to know more.

Field Guides are a great source of information. There are a number of other field guides available including specific guides to fossil and gemstones. Some excellent field guides are:

	Simon & Schuster’s Guide to Rocks and Minerals (ISBN 0-671-24417-5), my personal favourite.
	Eyewitness Handbooks Rocks & Minerals (ISBN 0-7737-2575-X), a fabulous book for the beginning rockhound.

For kids, there are a variety of books on rocks & minerals. Some really good ones are:

Eyewitness Books Rocks & Minerals (ISBN 0-7737-2180-0)

Looking at pictures of rocks & minerals & getting familiar with what they look like will also help you identify minerals. For photographs on the web of minerals, check out the Mineral Identification web sites listed below.

	Mineralogy Database
	Mineral Identification  Maintained in Australia
	Minerals by Class  Maintained by Amethyst Galleries Inc.
	Minerals by Name  Maintained by Amethyst Galleries Inc.

Characteristics used in the identification & study of minerals. These are the most common characteristics used when describing minerals.

	Color – this varies depending on the chemicals present and is the least informative in identifying a mineral variety
	Luster – what the surface looks like in the light
	Specific Gravity – how heavy it feels, heft
	Crystal Form – shape of crystal, shape the mineral would take if it had room to grow in a cavity, not massive – some minerals have a number of different crystal shapes
	Cleavage – pattern when mineral is broken – in planes or conchoidal
	Fracture
	Tenacity - toughness, how cohesive the mineral is, if it falls apart
	Hardness – what it can scratch & what scratches it
	Transparency - The ability to transmit light. Depending on a number of things, rocks & minerals can also transmit light. Many rocks that are opaque when in a chunk, are translucent when cut into very thin slices. Gems stones are often valued on how clear, or transparent they are.
	Special Properties– magnetism, chatoyancy, fluorescence, odor, streak, burn test, conductivity

Although most people think of color as an important characteristic of a specimen, it is not very useful in identifying a mineral.

	color is one of the physical properties most commonly used to describe minerals, but it is not a very good property to use to identify minerals
	some minerals are nearly always the same color like azurite (blue) and sulfur (yellow)
	many minerals come in a variety of colors – the changes are caused by slight chemical impurities or through exposure to heat
	color can change when the surface is exposed to moisture & air – it tarnishes or oxidizes
	some minerals have common names (varietal names)  that describe a specimen with a certain color eg. Quartz – rock crystal (colorless), smoky quartz (brown), citrine (yellow), amethyst (violet), rose quartz (pink)
	color can be described as metallic or non-metallic and is often described along with luster though they are 2 different characteristics
	rocks are often distinctive or named because of a certain color which occurs because of their mineral content

Other words to describe the intensity of colors:

	dark, very dark, light, pale
	deep
	dull, shiny
	bright

Words that describe how color is distributed:

	streaked
	splotchy, mottled, speckled
	layered, banded

	shiny, sparkly
	shimmering, opalescent
	frosted, milky

	So if you have a bucket of silver, it would weigh 10 times as much as a bucket of water. If you have a bucket of calcite, it would only weigh about 2 1/2 times as much as a bucket of water. That is why we think of metals as being "heavy". They are heavy compared to other things that we are used to picking up. This is also known as the "heft" of an object.
	The average rock you would pick up has an SG of about 2.75 because most of the earth’s crust is made up of quartz, calcite & feldspar.
	When something feels heavy, it feels heavier than expected for something of that size. How hefty a specimen feels has to do with how dense it is, its mass compared to its volume.

When minerals have the time & space to grow into their crystal forms,
they grow to beautiful regular shapes that are easy to recognize once you have seen a few examples.
Some words used to describe crystal forms or shapes are:

	acicular / radiating needles ~ crystals that grow in fine needles
	blebs ~ rounded blobs
	botryoidal ~ looks like top of bunch of grapes
	concretion ~ spherical, round shape that is solid, the same all the way through or filled with layers or agate
	cubic ~ 6 equal, square faces
	dendritic ~ branching, tree-like, looks like the veins in a leaf or like a painted “tree shape”
	dodecahedron ~ 12 sided, like a 12 sided die
	dog-tooth ~ shaped like the canine tooth, like a dog's tooth
	fibrous ~ looks like fibers, threads, parallel lines
	geode ~ spherical, round shape that is hollow inside, often lined with crystals
	hexagonal prism with pyramid termination ~ hexagonal cross-section, with pointy ends (terminations)
	hexagonal prism with rounded ends ~ 6 sided cross-section, with rounded ends
	hexagonal pyramid ~ sharp 6 sided pyramid, often seen in clusters
	mamilliary ~ rounded like botryoidal but a bit bigger than a bunch of grapes
	massive ~ a chunk of mineral with no crystal shape evident
	octahedral ~ 8 sided
	prismatic ~ like a prism with flat ends, longer than it is wide
	pyritohedral ~ 12 sided with 5 sided pentagon faces
	rose shaped ~ looks like a flattened flower or rose with petals
	tabular ~ divide easily into thin plates or sheets, a stack is know as a “book”
	termination ~ the end of a complete crystal

Cleavage is when a mineral breaks with smooth flat surfaces.
Cleavage can be described as perfect, good, imperfect, poor.
It can also be described as:

	Perfect 1 way ~ breaks on one perfect cleavage plane, crystals break into slices, sheets peel off
	Perfect 2 ways ~ breaks into elongated boxy shapes, 90 degree angles
	Perfect 3 ways ~ breaks into perfect rhombs, pieces look like squished boxes
	No cleavage ~ does not break regularly

Fracture is when a mineral breaks, but the surface is not regular, does not show cleavage.
Words that describe what a break in a rock or mineral looks like:

	conchoidal ~ curved break like what happens with thick glass or bottle bottom, shell shaped, can be rough or smooth
	jagged ~ metals, sharp point that scratches or snags fingertips, hackly
	splintery ~ fibrous
	uneven ~ rough surface, not smooth

	elastic ~ can be bent & when let go they resume their previous shape ~ mica
	ductile ~ can be pulled to make very thin threads ~ gold
	flexible
	fragile ~ break into pieces easily
	friable ~ crumbles easily
	malleable ~ flatten out into thin sheets without breaking ~ gold
	sectile ~ can be cut with a blade to make shavings ~ gypsum
	tough

MOHS SCALE OF HARDNESS - a scale devised by Friedrich Mohs
Scratching tools: 

	fingernail (2.2)
	copper penny (3.5)
	pocket knife or common nail (5.2)
	piece of glass (5.5)
	steel file or concrete nail (7.5)
	piece of corundum (9)

Notes for testing:

	Each mineral can scratch the minerals with lower hardness ratings.
	Each mineral can scratch itself.
	Don’t press hard, normal scratching should do.
	Weathered surfaces are softer.
	Corners or edges of crystals are softer.
	Small pieces seem softer than large pieces.
	When you scratch, take a close look at the scratch line - which often looks white. Is it really a scratch or is it a powder line made from the tool you used because it was softer than the item you were trying to scratch?

	acicular / radiating needles ~ crystals that grow in fine needles
	adamantine ~ very shiny like a gemmy crystal,  almost brilliant
	botryoidal ~ looks like top of bunch of grapes
	chatoyant ~ shines like a cat’s eye because of fibers
	chemicals ~ everything on earth is made up of the 103 known chemical elements, including rocks, mineral, air, water, plants & animals
	cleavage ~ the property to break along smooth lines or planes, the mineral has a shape it wants to be & breaks along those lines to keep that shape
	conchoidal ~ curved break like what happens with thick glass or bottle bottom, shell shaped, can be rough or smooth
	concretion ~ spherical mass that is separate from the rock around it, usually weathers out of host rock, grows from the inside out
	crystal shape ~ the form or habit of a mineral, the shape that the mineral takes if it has the time & space to grow properly
	crystals ~ minerals that form slowly have a distinctive crystal shape
	cubic ~ 6 equal, square faces
	dendritic ~ branching, tree-like growths
	dog-tooth ~ shaped like the canine tooth, like a dog's tooth
	dull / earthy ~ very dull, mainly in minerals that are porous
	earth's Crust ~ the earth's crust is made of solid, hardened rocks & minerals
	erosion ~ the process through which mountains are broken down into boulders & sand
	fossil ~ the remains of plants & animals that have been replaced by minerals
	fracture ~ is the way a mineral breaks when it won’t break on a cleavage plane
	gemstones ~ rocks & minerals that have been cut & polished, used for decoration and are usually rare and valuable
	geode ~ a sphere with a hollow inside, often lined with crystals, grows from the outside in
	geologist ~ a scientist that studies rocks & minerals and the earth sciences
	glassy ~ shiny like glass, found in 70% of minerals, vitreous
	hardness ~ how easy it is to scratch a mineral
	hexagonal prism with pyramid termination ~ hexagonal cross-section, with pointy ends
	igneous ~ rocks made from fire & heat, liquid magma that has cooled to form rocks
	luster ~ how shiny something is; words used to describe the way light reflects off of the surface of a specimen
	massive ~ a mineral with no distinct crystal shape, large chunk of inter-grown minerals
	matrix ~ the host rock that a mineral specimen or crystal is found in or on, bedrock
	metallic ~ shiny like polished metal, highly reflective, usually opaque
	metamorphic ~ igneous or sedimentary rocks that have been changed through extreme heat & pressure due to movement of the earth’s crust
	mineral ~ non-living matter, chemically the same all the way through
	minerals ~ all rocks are made of one or more of the 3000 known minerals
	no cleavage ~ does not break regularly
	opaque ~ cannot see through it at all, blocks all light, casts a solid shadow, acts like a wall
	paleontologist ~ a scientist who studies paleontology, learning about the forms of life that existed in former geologic periods, chiefly by studying fossils
	pearly ~ like a pearl, play of colors on surface
	physical properties  ~ the common visible and tangible characteristics used in the identification & study of minerals
	rockhound ~ a lover of rocks, minerals & fossils who collects specimens in the field
	rocks ~ non-living matter, made of 2 or more minerals
	rock cycle ~ rocks are constantly forming, wearing down and forming again, very slowly however
	schiller ~ colors shimmer or flash when the light hits the surface in a certain way
	sedimentary ~ layers of sand, clay & bits of rock laid down by water & turned to rock, often contains fossils
	specific gravity ~ how heavy something feels when compared to what you would expect, heft, weight, mass, density
	sub-metallic ~ soft shine like dull metal
	tabular ~ divide easily into thin sheets, a stack is know as a “book”
	termination ~ the point at the end of a crystal
	translucent ~ see shadows and shapes through it when held up to the light, details not clear, is frosted or cloudy, like looking through wax paper or light
	transparency ~ describes if you can see through something or not
	transparent ~ clear, see through clearly all the way, like a plain window glass or clear plastic wrap, “gemmy” like a gemstone
	uneven fracture ~ rough surface, not smooth
	vitreous ~ shiny like glass, found in 70% of minerals, glassy
	waxy ~ looks softly shiny like wax, like the surface of a wax candle