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Hands
On Experience Lab
Based on The Ontario Curriculum
Prepared by: Elfi Berndl, RocksForKids.com
1999
Workshop Site: Rock of Ages Lapidary
Warehouse, Maple Ontario Canada
Station A - ROCKS
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1 ) Difference between Rocks & Mineral
Learning Outcome(s)
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Gr. 4 ESS4 describe the difference
between minerals (composed of the same substance throughout) and rocks
(composed of two or more minerals)
- Gr. 7 ESS6 distinguish between rocks and minerals and describe the
differences in their composition (e.g. minerals, such as the mineral
calcite, are components of rocks such as sedimentary rock limestone,
in which calcite is found)
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Information:
Minerals
- all rocks are made of one or more of the 3000 known minerals
- minerals are the same all the way through
Rocks
- rocks are made of 2 or more minerals
All rocks are made of minerals, but minerals are not made of rocks. That is
one reason we speak of a sample or a specimen rather than a rock.
That piece of non-organic Earth’s crust could be a mineral instead of a rock.
Rock & Mineral Field Guides are an excellent source of information. An
excellent guide is Simon & Schuster’s Guide to Rocks and Minerals (ISBN
0-671-24417-5), my personal favourite. There are a number of other field guides
available including specific guides to fossil and gemstones.
Have students look at a variety of books on rocks & minerals, such as
Eyewitness Books Rocks & Minerals (ISBN 0-7737-2180-0), to see if they can
find the rock & mineral samples they will encounter at all of the stations.
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2) The Earth’s Crust Learning Outcome(s)
- Gr. 7 ESS4 describe the composition of the earth’s crust
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Information:
Below the loose layer of soil, sand & crumbled rocks found on Earth is
bedrock, which is a solid rock.
- The Crust makes up less than 1% of the Earth’s mass (0.4%) It is
made of oxygen, magnesium aluminum, silicon calcium, sodium potassium, iron.
There are 8 elements that make up 99% of the Earth’s crust. The continents
are about 35 km thick and the ocean floors are about 7 lm thick.
- The Mantle is the solid casing of the Earth and is about 2900 km
thick. It makes up about 70% of the Earth’s mass (68.1%). It is made up of
silicon, oxygen, aluminum and iron.
- The Core is mainly made of iron and nickel and makes up about 30%
of the Earth’s mass (31.5%). The Outer Core is 2200 km thick and is liquid
and the Inner core is 1270 km thick and is solid.
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3) Igneous, Sedimentary & Metamorphic Rocks Learning
Outcome(s)
- Gr. 4 ESS6 recognize that there are three classes of rocks: igneous,
sedimentary, and metamorphic
- Gr. 7 ESS5 classify rocks and minerals, using their observations,
according to their characteristics and method of formation
- Gr. 4 classify rocks and minerals according to chosen criteria,
relying on their observations (e.g. color, texture, shape)
- Gr. 7 classify rocks and minerals, using their observations,
according to their characteristics and method of formation
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Information:
The Earth’s crust is made of 3 kinds of rocks: igneous, sedimentary and
metamorphic. These groupings refer to how the rocks are formed.
Igneous Rocks
- Igneous rocks form when molten lava (magma) cools and turns to solid rock.
The magma comes from the Earth’s core which is molten rock. The core makes
up about 30% of the Total Earth Mass (31.5%)
- There are 5 kinds of igneous rocks, depending on the mix of minerals in the
rocks.
- Granite contains quartz, feldspar & mica
- Diorite contains feldspar & one or more dark mineral. Feldspar is
dominant.
- Gabbro contains feldspar & one or more dark mineral. The dark minerals
are dominant.
- Periodotite contains iron and is black or dark.
- Pegmatite is a coarse-grained granite with large crystals of quartz,
feldspar and mica.
- Obsidian is nature’s glass. It forms when lava cools quickly on the
surface. It is glassy and smooth.
- Pumice is full of air pockets that were trapped when the lava cooled when
it frothed out onto the surface. It is the only rock that floats.
Sedimentary Rocks
- Sedimentary rocks cover 75% of the earth’s surface. Most of the
rocks found on the Earth’s surface is sedimentary even though
sedimentary rocks only make up less than 5% of all the rocks that make
up Earth.
- When rocks are exposed to the elements – air, rain, sun, freeze/thaw
cycle, plants – erosion occurs and the little bits of rock worn away get
deposited as sediments. Over time, these sediments harden as they get buried
by more sediments and turn into sedimentary rocks.
- Sedimentary rocks are usually formed in layers (strata).
- There are 6 main kinds of sedimentary rocks depending on the appearance of
the rock.
- Conglomerate rock has rounded rocks (pebbles, boulders) cemented together
in a matrix.
- Sandstone is a soft stone that is made when sand grains cement together.
Sometimes the sandstone is deposited in layers of different coloured sand.
- Shale is clay that has been hardened and turned into rock. It often breaks
apart in large flat sections.
- Limestone is a rock that contains many fossils and is made of calcium
carbonate &/or microscopic shells.
- Gypsum, common salt or Epsom salt is found where seawater precipitates the
salt as the water evaporates.
- Porphyry rock is when jagged bits of rock are cemented together in a
matrix.
Metamorphic Rocks
- Metamorphic rocks are the least common of the 3 kinds of rocks. Metamorphic
rocks are igneous or sedimentary rocks that have been transformed by great
heat or pressure.
- Foliated metamorphic rocks have layers, or banding.
- Slate is transformed shale. It splits into smooth slabs.
- Schist is the most common metamorphic rock. Mica is the most common
mineral.
- Gneiss has a streaky look because of alternating layers of minerals.
- Non-foliated metamorphic rocks are not layered.
- Marble is transformed limestone.
- Quartzite is very hard.
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Top
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1) Physical Properties of Minerals Learning Outcome(s)
- Gr. 4 classify rocks and minerals according to chosen criteria,
relying on their observations (e.g. color, texture, shape)
- Gr. 7 classify rocks and minerals, using their observations,
according to their characteristics and method of formation
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Information:
Physical Properties of Minerals
Characteristics used in the identification & study of 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
Shape of Crystal or Habit – shape 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
Toughness – how cohesive the mineral is, if it falls apart
Hardness – what it can scratch & what scratches it
Special Properties– magnetism, chatoyancy, fluorescence, odor, streak,
burn test
These are the most common characteristics used when describing minerals.
Crystals are formed when minerals are allowed to grow without interference. The
atoms want to hold together in a pattern.
Specific Gravity ~ Indicates how many times
more the mineral weighs compared to an equal amount of water (SG 1)
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Description |
SG |
Mineral examples |
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very light |
< 2 |
borax |
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light |
2 – 3 |
quartz, calcite, halite, dolomite, ulexite, gypsum, turquoise, talc,
muscovite, biotite |
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heavy |
3 – 5 |
barite, chalcopyrite, fluorite, celestite, apatite, almandine garnet |
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very heavy |
5 – 10 |
nickel-iron, galena, pyrite, magnetite |
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extremely heavy |
> 10 |
silver, gold |
Hardness ~ Based on Mohs Table of Hardness
- 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)
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Rating |
Description |
Mineral example |
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1
SOFT
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Easily crumbles. Can be scratched with a fingernail (2.2). |
Talc |
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2 |
Can be scratched with a fingernail (2.2).
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Gypsum
Soapstone (impure talc)
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3 |
Can be scratched with a copper penny (3.5). |
Calcite |
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4 |
Can be scratched with a pocketknife (5.2) or common nail. |
Fluorite |
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5 |
Can be scratched with a pocketknife (5.2) or common nail.
Can be scratched with a piece of glass (5.5).
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Apatite |
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6 |
Mineral of hardness 6 or more will scratch glass. |
Feldspar -
Orthoclase
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7 |
Can be scratched with a steel file (7.5) or a concrete nail. |
Quartz |
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8 |
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Topaz |
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9 |
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Corundum |
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10
HARD
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Diamond |
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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.
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Transmitting Light Through Minerals ~
A
mineral can be
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transparent |
- clear, see right through it when it is sliced thin
- called "gemmy", desirable for gemstones
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- quartz crystal, celestite, selenite |
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translucent |
- see shapes & shadows through it when it is sliced thin
- chemical impurities can cause the mineral to be cloudy
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- calcite, quartz, sphalerite |
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opaque |
- can’t see light through it at all when it is sliced thin
- rarely used for gemstones
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- metals, gypsum, |
Colour
- although color is one of the first things noticed about a mineral specimen,
it is not a good characteristic to use to identify a mineral
- variations in color are produced by traces of other chemicals being
present in the mineral
- quartz is one mineral that comes in many colours and the colours and
how they are distributed in the quartz mineral give the quartz different
common names such as : rock crystal (clear & transparent), amethyst
(purple), smoky quartz (brown), rose quartz (pink), milky quartz
(white), blue quartz (blue), chrysoprase (green, translucent), agate
(bands of colours), jasper (yellow to red), carnelian (orange-red),
heliotrope (opaque green with red dots)
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Colour Vocabulary
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white |
colorless |
clear |
beige |
dirty-white |
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red |
purple |
mauve |
pink |
salmon pink |
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blue |
bluish |
turquoise |
green |
silvery -yellow |
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gray |
silver |
black |
golden |
gold-colored |
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yellow |
bronze |
brown |
creamy |
copper-colored |
| Other words to describe
color |
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deep |
shiny |
dull |
dark |
very dark |
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light |
pale |
bright |
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| Words that describe how color is
distributed |
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splotchy |
streaked |
layered |
speckled |
banded |
Luster Vocabulary ~ words used to describe the way light reflects off of
the surface of a mineral
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Word |
Description |
Example |
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dull / earthy |
very dull, mainly in minerals that are porous |
kaolinite, orthoclase |
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waxy |
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opal, chalcedony |
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greasy / oily |
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nepheline |
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pearly |
like a pearl, play of colours, light |
talc, some micas |
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silky |
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some varieties of gypsum, kernite, ulexite & in fibrous minerals |
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glassy / vitreous |
looks like glass |
quartz, many rock-forming minerals
obsidian – "nature’s glass" |
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resinous |
looks like freshly-broken shellac, usually yellow-brown |
sphalerite |
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adamantine |
high lustre, almost brilliant |
sphalerite |
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submetallic |
silvery or metallic lustre but mineral is transparent or translucent
when in small slivers |
hematite |
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metallic |
highly reflective, opaque minerals |
pyrite, gold, silver |
| Other words that describe
luster |
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shiny |
sparkles |
milky |
shimmering |
opalescent |
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frosted |
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Station C – FOSSILS, EROSION & OTHER INTERESTING THINGS
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1) Fossils Learning Outcome(s)
- Gr. 4 ESS10 identify and describe rocks that contain records of the
earth’s history (e.g. fossils), and explain how they were formed
- Gr. 7 ESS11 analyze, through observation, evidence of geological
change (e.g. fossils, strata)
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| Information:
Fossils occur when the remains of plants and dead animals are covered by
sediment. After many years, minerals replace the organic material. Fossils are
usually found in sedimentary rocks. Fossils are harder than the surrounding
matrix and often "weather out" intact. |
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2) Erosion Learning Outcome(s)
- Gr. 4 ESS2 investigate, test and compare the physical properties of
rocks and minerals and investigate the factors that cause erosion of the
landscape
- Gr. 7 investigate the effect of weathering on rocks and minerals
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| Information:
When rocks & minerals are exposed to the elements, erosion occurs.
Weathering is when the rock is worn down by the effects of the weather. Erosion
is when the bits & pieces of the rocks that break off get moved by water,
wind or ice.
Soil is made of bits of rocks &minerals, decomposed plants & animals.
It takes 250 to 1000 years to make 3 cm of topsoil.
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3) Unique Rocks & Minerals from Around the World
Learning Outcome(s)
- Gr. 4 ESS7 compare different rocks and minerals from the local
environment from the local environment with rocks and minerals from
other places
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Students to sort through the pile of rocks & see if they can find similar
ones to the ones on display at the other stations. Using an identification book
and their knowledge, try to sort the rocks into similar piles.
Determine which rocks are found in Canada.
Identify rocks that are unique to a specific location such as Utah Septarian
Nodule, Brazilian Amethyst Geode, African Tiger’s Eye, and Canadian
Labradorite.
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