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 1) Difference between Rocks & Mineral
2) The Earth's Crust
3) Igneous, Sedimentary & Metamorphic Rocks
Station B - Minerals 1) Physical Properties of Minerals
Station C - Fossils, Erosion and Other Interesting Things 1) Fossils
2) Erosion
3) Unique Rocks & Minerals from Around the World

 

Station A - ROCKS

1) Difference between Rocks & Mineral Learning Outcome(s)

  • 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)

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.

2) The Earth’s Crust Learning Outcome(s)

  • Gr. 7 ESS4 describe the composition of the earth’s crust
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.

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
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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Station B – MINERALS

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
Information:

Physical Properties of Minerals

Characteristics used in the identification & study of minerals

  1. Color – this varies depending on the chemicals present and is the least informative in identifying a mineral variety
  2. Luster – what the surface looks like in the light
  3. Specific Gravity – how heavy it feels, heft
  4. 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
  5. Cleavage – pattern when mineral is broken – in planes or conchoidal
  6. Toughness – how cohesive the mineral is, if it falls apart
  7. Hardness – what it can scratch & what scratches it
  8. 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)

Description

SG

Mineral examples

very light

< 2

borax

light

2 – 3

quartz, calcite, halite, dolomite, ulexite, gypsum, turquoise, talc, muscovite, biotite

heavy

3 – 5

barite, chalcopyrite, fluorite, celestite, apatite, almandine garnet

very heavy

5 – 10

nickel-iron, galena, pyrite, magnetite

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)

Rating

Description

Mineral example

1
SOFT

Easily crumbles. Can be scratched with a fingernail (2.2).

Talc

2

Can be scratched with a fingernail (2.2).

Gypsum
Soapstone (impure talc)

3

Can be scratched with a copper penny (3.5).

Calcite

4

Can be scratched with a pocketknife (5.2) or common nail.

Fluorite

5

Can be scratched with a pocketknife (5.2) or common nail.
Can be scratched with a piece of glass (5.5).

Apatite

6

Mineral of hardness 6 or more will scratch glass.

Feldspar -
Orthoclase

7

Can be scratched with a steel file (7.5) or a concrete nail.

Quartz

8

 

Topaz

9

 

Corundum

10
HARD

 

Diamond

Notes for testing:

  1. Each mineral can scratch the minerals with lower hardness ratings.
  2. Each mineral can scratch itself.
  3. Don’t press hard, normal scratching should do.
  4. Weathered surfaces are softer.
  5. Corners or edges of crystals are softer.
  6. Small pieces seem softer than large pieces.

Transmitting Light Through Minerals ~ A mineral can be

transparent

     
  • clear, see right through it when it is sliced thin
  •  
  • called "gemmy", desirable for gemstones

- quartz crystal, celestite, selenite

translucent

     
  • see shapes & shadows through it when it is sliced thin
  •  
  • chemical impurities can cause the mineral to be cloudy

- calcite, quartz, sphalerite

opaque

     
  • can’t see light through it at all when it is sliced thin
  •  
  • rarely used for gemstones

- 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)

 

Colour Vocabulary

white

colorless

clear

beige

dirty-white

red

purple

mauve

pink

salmon pink

blue

bluish

turquoise

green

silvery -yellow

gray

silver

black

golden

gold-colored

yellow

bronze

brown

creamy

copper-colored

Other words to describe color

deep

shiny

dull

dark

very dark

light

pale

bright

   
Words that describe how color is distributed

splotchy

streaked

layered

speckled

banded

Luster Vocabulary ~ words used to describe the way light reflects off of the surface of a mineral

Word

Description

Example

dull / earthy

very dull, mainly in minerals that are porous

kaolinite, orthoclase

waxy

 

opal, chalcedony

greasy / oily

 

nepheline

pearly

like a pearl, play of colours, light

talc, some micas

silky

 

some varieties of gypsum, kernite, ulexite & in fibrous minerals

glassy / vitreous

looks like glass

quartz, many rock-forming minerals

obsidian – "nature’s glass"

resinous

looks like freshly-broken shellac, usually yellow-brown

sphalerite

adamantine

high lustre, almost brilliant

sphalerite

submetallic

silvery or metallic lustre but mineral is transparent or translucent when in small slivers

hematite

metallic

highly reflective, opaque minerals

pyrite, gold, silver

Other words that describe luster

shiny

sparkles

milky

shimmering

opalescent

frosted

       

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Station C – FOSSILS, EROSION & OTHER INTERESTING THINGS

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)
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.

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
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.

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
Activity:

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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