bold underlined - GemKids€¦ · What’s the difference between weathering and erosion?...

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Items with an asterisk and in italics are not meant to be read aloud.

We strongly encourage you to download the notes, which provide

more detailed explanations of the slides.

Words that are all capitalized in gold and underlined in the Power Point

presentation are to be written in the student’s GIA Junior Gemologist

Program workbook.

These words are also bold and underlined in the notes section.

• Welcome to the (spell out) G. I. A. Junior Gemologist Program.

• GIA stands for the Gemological Institute of America.

• Ready to have some fun?

• *Review class objectives with the students by reading slide content.

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• Please open your workbooks to page 3.

• *Read slide content first.

• Geology helps gem prospectors decide where to look for new gem sources.

• They know that certain gem deposits are associated with certain types of

rock.

• This helps them narrow down the search for gems.

• The image of the green mountain shows a Colombian emerald mine. See one

of the openings to the inside of the mine?

• The other image shows an ice road with ice road trucks in the far distance

delivering equipment to a Canadian diamond mine.

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• Please write down on the blank line on page 3.

• This is Dona Dirlam. She is Director of the Richard T. Liddicoat Gemological

Library and Information Center at GIA in Carlsbad, California.

• She is a geologist and a gemologist.

• The picture on the right shows a geologist who was once an editor for the

“Gems & Gemology” journal. He is about to enter a tanzanite mine in

Tanzania, Africa.

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• Please turn to page 4.


• All rocks are made of minerals.

• Some rocks form at or near the earth’s surface and yet others form deep in

the earth’s crust or in the middle layer of the earth called the mantle.

• Example

• Think about rocks like cookies. Cookies are made with more than one

ingredient, just like rocks.

• Some of those ingredients you can see, for example: nuts, chocolate chips,

and oatmeal.

• Some ingredients you can’t see like eggs, sugar, salt, and baking powder.

• Rocks are made of many minerals, some you can see and some you cannot,

just like cookies.

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The Rock Cycle

• There are many kinds of rocks, but they all can be classified into three groups based on how they formed:

Igneous

Sedimentary

Metamorphic

• The rock cycle is a recycling process that never stops. It makes new rocks from old rocks.

• If the rocks are deep underground, they’re altered or melted by the earth’s inner forces.

• If they’re at the surface, weathering – exposure to water, wind and other environmental conditions – breaks them down.

• Erosion may move the rocks far from their original locations.

• The broken-down rocks can be buried, altered by pressure, or melted by high temperatures to begin the cycle again.

• Let’s talk more about each kind of rock formation process.

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• Intrusive igneous rocks are those that solidified or hardened below ground.

These rocks are formed when underground melted rock called magma is trapped deep within the earth.

Some magma may feed volcanoes on the earth's surface, but most remains trapped below, where it cools very slowly over thousands or millions of years until it solidifies.

When magma cools and hardens slowly, the individual minerals in it form large grains, or crystals, that are easy to see.

• Extrusive igneous rocks include all rocks resulting from eruptions of magma.

This rock is produced when magma exits and cools outside of, or very near, the earth's surface.

These are the rocks that form from erupting volcanoes and from cracks that ooze lava.

Magma, called lava when molten rock erupts on the surface, cools and solidifies almost instantly when it is exposed to the relatively cool temperature of the atmosphere.

Quick cooling means that mineral crystals don't have much time to grow, so these rocks have a very fine-grained or even glassy texture.

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• Please write down granite and lava on line 1, page 4.

(picture 1)

Granite is an intrusive igneous rock, which formed below the earth’s surface. It

had time to cool slowly and form large mineral crystals.

• These are granite boulders in a river. They originally formed underground, but

they’ve been exposed at the surface by weathering and erosion.

• Often times you can easily see the minerals, which can appear in different

shapes and colors.

• Have you seen the different colors in granite countertops? Those are different

mineral crystals.

• (picture 2)

• In the next picture you can see a lava flow, which is an extrusive igneous

rock.

• Lava cools very quickly so you can see lots of holes where gases bubbled

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out. It has a very rough texture.

• It’s harder to see the different mineral crystals because these rocks cool

relatively quickly, not allowing time for large crystal to grow.

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Some igneous rocks are associated with various gemstones.

(picture 1)

• Pink tourmaline crystals can be found with igneous deposits.

• This fine example comes from a mine in Southern California.

(picture 2)

• This igneous rock is called kimberlite.

• This rock can contain diamond crystals, such as this example from South

Africa.

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• Please write down sandstone on line 2, page 4.

• Sediments are tiny particles and when pressed together with pressure, they

become solid.

• So what do you think sandstone is made of? That’s right – sand.

• Notice the different colors of layers, and even some larger pebbles, in this

sandstone cliff located in Colorado Springs, Colorado.

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What are the names of the two processes that breakdown rocks?

• Weathering

• Erosion

What’s the difference between weathering and erosion?

Weathering is the breakdown of rocks.

• This is caused by the action of wind, rain, snow, and other types of weather

repeatedly hitting the surface of rocks.

• It is also caused by water, such as an ocean, lake or river, or even plant

growth, which breaks the rock down.

• The process happens in one place. There is no movement involved in

weathering.

As soon as a rock particle moves, it’s called erosion.

• We call it erosion if the rock particle is moved by some flowing agent such as

streams, glaciers, waves, wind, and underground water.

• This is a picture of a sandstone deposit that was taken in 1890 in Oregon.

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• Look at Jump-Off Joe, looks pretty solid right? Yes.

• Let’s see what happens after 100 years of weathering and erosion.

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(picture 1)

Jump-Off Joe underwent 20 years of weathering and erosion.

Notice the rough texture as the rock breaks down with the waves constantly

pounding it.

(picture 2)

After 30 years of weathering, the hole in the front is much larger and the arch is

getting bigger.

(picture 3)

After 80 years of weathering, there’s only a few small rock particles left.

(picture 4)

After 100 years of weathering and erosion this is all that is left of Jump-Off Joe.

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After seeing what happened to Jump-Off Joe, do you think this house is safely

grounded on this coastal cliff in Dana Point, California?

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Some gemstones are formed by the sedimentary process.

(picture 1)

• Black opal from Lightning Ridge, Australia, forms this way.

• Black opal is the most prized variety due to its striking array of colors.

(picture 2)

• Turquoise is another beautiful gem material.

• These examples come from the Sleeping Beauty Mine in Arizona.

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• Please write down slate on line 3, page 4.

• Metamorphic rocks can form from any type of rock, including other

metamorphic rock.

• This is an example of mountain building in action.

• Can you believe that this area was flat at one time? Nature deposits

everything horizontally, due to gravity.

• Changes occurring in the earth have caused this mountain to be squeezed,

making it look wavy.

• This mountain is a combination of limestone and slate.

• Example

• Let’s look at something we all know about…recycling. Plastic soda bottles are

melted and pulled to produce fiber filling for pillows, quilts and jackets.

• This is similar to what happens to rocks during the metamorphic process.

They are completely changed.

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So where do these changes in the earth occur for metamorphic rocks to form?

• The entire earth is made of up of tectonic plates, like giant pieces of a puzzle.

• Some have land on top and some are submerged on the ocean floor.

• They are all riding on top of molten magma, which constantly moves them

around.

• As they collide into each other, huge amounts of heat and pressure form,

changing existing rock into new rock.

• If the right chemical elements are present, gemstones can crystalize.

• For example, emerald, sapphire, ruby and jade are found in the Himalayas,

the world’s tallest mountain range.

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• Please write down marble on line 3, page 4.

• Here is a picture of the Himalayas today. Notice how sharp and jagged the

surface terrain is as the mountains climb high into the sky.

• Marble, once a sedimentary rock called limestone, forms in areas like this

where it was subjected to intense heat and pressure.

• Spinel is a gemstone that can form in marble.

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• Please turn to pages 6-7 in workbook.


• We already discussed that rocks are made of minerals. So mineralogy is the

study of those individual minerals that make up rocks.

• Scientists have identified roughly 3,000 minerals on earth.

• The pink mineral is morganite. The other image shows talc.

Example

• Think about minerals like the ingredients in cookies. Mineral crystals in rocks

are like the large ingredients you can see in a cookie: chocolate chips,

oatmeal, M&M’s, etc.

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• Please write down mineralogist on the blank line on page 7.

• This is Mr. Richard T. Liddicoat (LID-EE-COAT). He was instrumental in

developing ways to identify gemstones.

• He served GIA for over 60 years.

• To be considered a mineral, a material must have five specific features. Let’s

explore each one now.


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*Read slide content first.

• Please write down solid on line 1 on page 8.

• All minerals have to be solid, which means not a liquid or a gas.

• So do you think you can drink a mineral? No.

• This is a red ruby crystal growing with its host rock marble.

• Let’s see what the next feature is.

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• Please write down inorganic on line 2 on page 8.

• Inorganic means that it is non-living; it’s never been alive.

• This is an aquamarine crystal that likely formed in a cave in the earth.

• Miners had to chip it out of a cave wall, using shovels and picks, for us

to see its beautiful form.

• Aquamarine is the bluish variety of the gem family beryl.

• Optional:

• So why is a pearl a gem if it comes from a mollusk or oyster, which are

living creatures?

• Pearl is considered an organic gem material, which means that it’s a

byproduct of a living plant or animal.

• Other examples of organic gems:

• Amber – fossilized tree resin

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• Coral – created by tiny animals

• Ivory – tusks of elephants, walruses, or other animals

• Mother of pearl – inside of a sea shell

• It’s a gemologist’s job to learn to separate minerals from organic gem

material.

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• Please write down made by nature on line 3 on page 8.

• Minerals have to be naturally occurring, that means they are made by nature.

Not made by human hands.

(picture 1)

• These are natural sapphire crystals next to faceted, or cut, gemstones.

• Most people are familiar with blue sapphire, but it comes in other colors like

orange, yellow and many more.

• Natural crystals typically form in angular, geometric shapes.

(picture 2)

• Scientists have learned how to create sapphire in a laboratory.

• We call it synthetic sapphire, like this example.

• A synthetic has the same properties as a natural, the difference is that it was

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made in a laboratory and not in nature.

• This rounded synthetic material that is formed in the laboratory is called a

boule (BOOL).

• Notice how clean and rounded the laboratory material is compared to the

natural angular crystals.

• A gemologist may be able to tell them apart by their shape, but once they are

cut it’s much more difficult to tell them apart.

• A gemologist needs to perform more tests with specialized equipment to

identify them.

• Why is this important? Because natural sapphire is more valuable than

synthetic because it’s much harder to find.

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Please write down crystal structure on line 4 on page 8.

One exciting aspect of minerals is their beautiful and elegant crystal forms.

• This is a natural emerald crystal.

• Notice how it has six sides and a flat top and bottom – we call this shape

hexagonal (HEX-AG-O-NAL).

• GIA classifies minerals into seven different crystal systems, or shapes.

• This emerald crystal looks rather large next to the cut gemstone, but in reality,

emerald crystals don’t get really large because of the environment they form

in.

• This crystal is probably 1 inch (25.4 millimeters) tall.

• Other minerals can get quite a bit larger. Do you think there are crystals that

can get bigger than a human?

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•

•

•

•

•

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• Please write down chemical composition line 5 on page 8.

• This is the final feature of a mineral.

• A specific chemical composition means that it has a recipe of the correct elements

present.

• The recipe has to be perfect to grow different kinds of minerals.

• This blue sapphire’s chemical composition consists of atoms of aluminum, oxygen,

iron and titanium.

Example

• Let’s say I want to make chocolate chip cookies but I have no chocolate chips.

Can I substitute raisins and oatmeal and still have chocolate chip cookies?

No.

• You need to have the right ingredients for cookies or minerals.

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Example: Cookies bake for 10-15 minutes in an oven heated to around 350

degrees.

• Can you bake cookies at 350 degrees for 5 hours and get perfect

cookies? No, they’ll burn.

• Can you bake cookies at 30 degrees for 10 minutes and get perfect

cookies? No, they’ll be undercooked.

• You need to have the right temperature and time for cookies and

minerals to grow.

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• Diamond and graphite have the same chemical composition; they are both

made of carbon.

• But diamond is the hardest mineral we know of and graphite is one of the

softest (graphite is mixed with clay and water and forms the “lead” in pencils).

• Can you write on a piece of paper with a diamond? No.

• Can you put graphite into a ring that will last forever? No.

• So what’s the difference? It’s how the carbon atoms are arranged.

• The atoms in diamond are arranged tightly, as they come together in

conditions of intense heat and pressure far under the earth’s crust.

• These tightly packed atoms make diamond the hardest known mineral.

• The atoms in graphite, which is used in pencils, are arranged very loosely

making it very soft.

• It’s so soft that little graphite particles slip off your pencil onto your paper –

that’s the writing you see.

• Graphite forms close to the earth’s surface where the heat and pressure are

not so intense.

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• Activity

• Let’s pretend our hands are carbon atoms.

• Put your hands together and rub them back and forth as if you were

trying to get warm.

• Do your hands slide easily?

• Yes, they do. That’s how the carbon atoms are arranged in graphite.

• They are very loose and slippery.

• Now, clasp your fingers together tightly and try to slide them back and

forth. Can you?

• No you can’t. This is how carbon atoms in diamonds are arranged, very

tightly making it very hard.

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• Let’s talk now about the Mohs (MOZE) Scale of Hardness

In the 1800s, a German mineralogist by the name of Friedrich Mohs determined how hard

minerals were by how they could scratch or not scratch each other.

• Hardness refers to a mineral’s resistance to being scratched.

The Mohs Hardness Scale ranges from 1 – 10

o 1 is the softest mineral, for example talc.

o Talc can be easily crushed into talcum powder, like baby powder, with your

fingers because it is so soft.

o On the other end of the scale is the hardest mineral, diamond, which is 10.

o Diamond can scratch everything below it.

o Do you know what will scratch diamond? Only another diamond.

o Corundum is very hard at 9. It’s the family name for sapphire and ruby.

Ruby is the red variety of corundum, any other color of corundum is

called sapphire.

o Corundum can scratch everything on the list below it but what can scratch

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corundum? Only diamond or another corundum.

o So do you think topaz can scratch calcite? Yes.

o Can fluorite scratch apatite? No.

o Good, you understand. The higher numbers on the scale can

scratch the softer minerals below.

Everyday examples:

• Glass-like plate at checkout counter at grocery store, where your groceries

are scanned, is synthetic sapphire (9).

• Emery board to file nails can be made with diamond (10), corundum (9), or

garnet (7).

• Even smart phones of the future may one day have faces made of synthetic

sapphire (9).

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• Are you ready for another activity?

• Look at the worksheet on page 11.

• Please write quartz – 7 after the words “tester mineral.”

• Can anyone tell me what the 7 stands for? It’s the hardness of quartz.

• First, copy the name of each mineral shown in the boxes on the screen onto

each corresponding line on your worksheet, for example write corundum in

box #1, etc.

• Now look at the Mohs Scale of Hardness on page 10 to find the hardness of

each mineral.

• Then write the hardness number next to the mineral on each line on your

worksheet, for example corundum - 9.

Don’t worry if the pictures on the screen look different from the pictures

on the Mohs Scale – minerals can come in different colors.

• Now using the Moh’s Scale, determine if the minerals in boxes 1-3 are harder

or softer than the tester mineral quartz.

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• Circle whether each mineral is harder or softer than the quartz in each

corresponding box.

Example:

• In box #1, do you think corundum will scratch quartz? If so circle “harder”. If

not circle “softer”.

• Do you think fluorite can scratch quartz?

• Will calcite scratch quartz?

Answers:

• #1 corundum – 9 – harder

• #2 fluorite – 4 – softer

• #3 calcite – 3 – softer

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• Many gems are minerals, but not all minerals are gems.

• There are three special features that a mineral must have in order to be

considered a gem.

• The minerals that can be considered gems are the best of the best.

• These are topaz gemstones. See the different colors they come in?

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Please write down gemologist on the line on page 12.

• This is a gemologist using special tools.

• She’s holding a black magnifying tool, called a loupe (LOOP), to examine a

gemstone that she holds in place with tweezers.

• Gemologists rely on gemological tools to help them identify gems.

• Let’s talk now about those three features that make a mineral a gem.

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• The first feature of a gem is that it must be beautiful.

• Please write down beautiful on line 1 on page 13.

• Beauty is what we call subjective, that means you and I may have different

opinions on what we think is beautiful.

• For example, do you think the outer arch of stones here is beautiful? Some

say yes, some say no.

• Guess what? These are diamond crystals. They do not always come from the

earth in a perfect shape.

• But if you give one of these crystals to a talented diamond cutter, he or she

can cut facets, like flat faces, onto the diamond’s surface which allows light to

come through it and gives us the sparkle and beauty we expect.

• I think we can all agree the diamond in the center is beautiful.

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• The second feature of a gem is that it is rare.

• Please write down rare on line 2 on page 13.

• Diamonds typically are colorless, or they appear to be clear.

• There are very special diamonds that come in a rainbow of colors, and they

are very rare. That means there are not that many of them and they are hard

to find.

Example:

• Can you go to the beach and easily bring back a bucket of sand?

Why? Because sand is everywhere at the beach

• Can you go to the beach and easily bring back a bucket of diamonds?

Why not? Diamonds are hard to find.

• Fancy colored diamonds, like these blue, yellow, green and pink ones,

are even more rare.

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• Note the rough, uncut stones behind each faceted gem. Gems look

quite different, and more beautiful, when they are cut.

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• The third feature of a gem is that it is durable.

• Please write down durable on line 3 on page 13.

• Durability is the combination of three factors.

• A gem has to be hard, tough and stable to be considered durable.

• Why do you think that’s important, especially with jewelry?

• Imagine if you had a ring made from talc, 1 on the Mohs Scale, and you wore

your ring in the shower. What do you think would happen to it?

• The water would weather it, or break it down, and it would erode, or wash

away, down the drain.

• Jewelry is meant to last for a long time so gems used in it need to be durable.

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Please turn to page 14 in workbooks.


• Inclusions are things we find inside of gems, often using magnification tools.

• Have you ever seen a cup of Jello with fruit chunks inside? Those fruit chunks

are similar to inclusions inside of gems.

• The fruit chunks are trapped inside of the Jello so they are included within it,

just like gemstones have inclusions within them.

• This image shows a lily-pad inclusion in a peridot (PER-UH-DOH).

• It’s not really a lily pad, but it looks like one and it is one of the clues to help a

gemologist identify the gem type.

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• This a picture of an emerald through a microscopic lens that shows a three-

phase inclusion. That means it contains the three phases of matter: solid,

liquid and gas.

On the left side is the faint outline of a mineral crystal, most likely

calcite. See how it has sharp angles?

Next to it, in the middle, is a gas bubble. Notice its round shape and

the bright spots near the top and right side, which are reflections.

There cannot be a bubble unless there is liquid so this pocket is

enclosed with liquid, a mineral, and a trapped gas bubble.

• Inclusions serve as fingerprints for gemstones since no two are alike.

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• Amber is tree resin that fossilized over the course of at least one million

years.

• Long ago, certain trees produced resin on the outside of the trunk that started

out in a very sticky state.

• Because it’s so sticky, it was easy for little bugs, critters, or plant parts, to get

stuck in it.

• As the trees died and became buried in the sediments, the resin began to

solidify.

• After one million years, this material is known as amber.

• Scientists have discovered many extinct species of bugs and plants

preserved in ancient amber.

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• Please turn to page 16 in workbooks.


• Phenomenal stones are different from other gems.

• They can change color in different lighting or reveal special effects.

• They are light reactive so you need a good light source to see them.

• This shows moonstone on the left; an opal in the middle, and a cat’s-eye

chrysoberyl (CRIS-O-BEAR-AL) ring on the right, surrounded with diamonds.

• Now let’s look at more examples of phenomenal stones.

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• Are you ready for your next activity?

• Please look at the worksheet on page 17.

• This worksheet has six different examples of phenomenal gems.

• As we go through the slides, please copy each picture and the name of each

gemstone into your workbook.

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*Read definition of stone 1 on slide first. Asterism (AS-TER-IS-M)

• This is a stone showing asterism, or star effect.

• Please draw this in the empty box on line 1.

• Write synthetic star ruby on line 1.

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*Read definition of stone 2 on slide first. Adularescence (AD-U-LAR-ES-

SENCE)

• This stone is showing a faint cloudy effect.

• See the bluish glow?


• Write moonstone on line 2.

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*Read definition of stone 3 on slide first. Aventurescence (A-VEN-TUR-ES-

SENCE)

• It looks like confetti is inside this stone.

• See the darker flecks of green?


• Write aventurine quartz on line 3.

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*Read definition of stone 4 on slide first. Chatoyancy (SHA-TOY-AN-CEE)

• This stone has a single band of light running through the center.


• Write cat’s-eye tourmaline on line 4.

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*Read definition of stone 5 on slide first. Iridescence (IR-I-DES-SENCE)

• This stone has lots of different rainbow colors.


• Write fire agate on line 5.

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*Read definition of stone 6 on slide first. Play-of-color

• This also has lots of rainbow colors, but they sparkle as light moves across

the stone.


• Write opal on line 6.

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Here they all are in case you need to catch up.



• Geologists, mineralogists, and gemologists all use a variety of tools to help

them examine and identify rocks, minerals, and gemstones. Here are some of

the more common ones:

Microscopes

Loupes

Penlights

Tweezers

Stone cloths

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• A microscope can magnify an object to many times its size.

• Depending on its “power”, it will magnify an object that many times. For

example: 64X, or 64 power, magnifies an object 64 times. That means that

your object will appear 64 times larger!

• It can help you see things that aren’t visible with your unaided eyes.

• Binocular microscopes are more comfortable to look through because

you use both of your eyes.

• You can use the stone holder to hold your gemstone so your hands are

free.

• Let’s see what some gems look like under the microscope.

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• Please turn to page 20 in workbooks.

*Click to reveal image.

• Gemstone 1

• Here is what a diamond looks like with the unaided eye.

*Click to reveal magnified image.

• This is what it looks like under the microscope.

• This may look like a soaring bird, but these are microscopic inclusions we call

feathers in diamonds.

• Please draw this image in box 1.

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• Gemstone 2

• Here is what a peridot looks like with the unaided eye.



• We call these lily pad inclusions, but they are actually stress fractures

surrounding crystals.

• Please draw these in box 2.

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• Gemstone 3

• Here is what a moonstone looks like with the unaided eye.



• We call these centipede inclusions, but they’re not really bugs. They are also

stress fractures in the gem.

• Please draw these in box 3.

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• Gemstone 4

• Here is what a amber looks like with the unaided eye.



• It looks like a mosquito and it really is one! Amber, fossilized tree resin,

preserves bugs, leaves and other plant parts that are at least one million

years old.

• Please draw this in box 4.

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• Look up your birthstones on pages 21-24 in your workbook. Here you will find

lots of interesting lore to read about your birthstone.

• “Lore“ means stories, myths, and fables about something.

• There’s a word search puzzle on page 25.

• A crossword puzzle on page 26.

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Don’t forget to check out more fun activities on our GemKids website!

Here’s the address for the website: www.GemKids.gia.edu

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Thank you to all our photographers!

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