| A
rock is made of grains of one or more minerals that fit together. |
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| 1. | Go
to Bitesize
from the BBC to find out how rocks change due to weathering. |
| 2. | Visit Exploring Earth to view an interactive rock cycle animation. |
| 3. | Can you finish this rock cycle diagram from The Learning Zone? |
| 4. | Fill in the Rock Chart by visiting the web sites listed below. |
| Find
information for your chart |
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Igneous |
Sedimentary |
Metamorphic These rocks are made when sedimentary and igneous rocks beecome changed by conditions underground. |
| Did
you know... Igneous means made from fire or heat. When volcanoes erupt and the liquid rock comes up to the earth's surface, then new igneous rock is made. When the rock is liquid & inside the earth, it is called magma. When the magma gets hard inside the crust, it turns into granite. Most mountains are made of granite. It cools very slowly and is very hard. 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. When
mountains are first formed, they are tall and jagged like the Rocky
Mountains on the west coast of North America. Over time (millions
of years) mountains become old mountains like the Appalachian Mountains
on the east coast of the United States. When they are old, they are
rounded and much lower. Metamorphic
rocks were originally igneous or sedimentary, but due to movement
of the earth's crust, were changed. Metamorphic rocks are the least
common of the 3 kinds of rocks. |
| Mohs
Scale of Hardness Friedrich
Mohs devised a hardness scale in 1812. |
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Talc |
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Used for talcum powder, paint, rubber and plastics, your fingernail can easily scratch it, feels greasy and has a translucent, soapy look |
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Gypsum |
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Used for plaster of Paris and household wallboard, can be found in beautiful crystal rose shapes |
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Calcite |
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Typically found in the sedimentary rock called limestone, is also in marble, a metamorphic rock, which forms when limestone is put under strong heat and pressure, forms stalactites and stalagmites, makes shells A great way to identify it is to drop a weak acid, like vinegar on it. Calcite will bubble. It also produces a double refraction of light, look though it at an image and you will see double! |
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Fluorite |
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Comes in many pretty colors, best known for purple, often fluorescent, transparent to translucent, Fluorine in fluorite prevents tooth decay, glass making, enamels, used to make high quality lenses for telescopes and cameras instead of glass |
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Apatite |
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Found in igneous, metamorphic and sedimentary rocks, usually in small amounts, usually green to blue, source of phosphorous used in fertilizer, its the mineral that makes up the teeth in all vertebrate animals, as well as their bones |
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Feldspar |
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Also known as orthoclase, milky variety called moonstone, used in ceramics and glazes, some show a milky translucence and occasionally used as gems |
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Quartz |
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The most common mineral on Earth, comes in many colors and shapes, but always has a glassy look, usually forms sedimentary rocks like sandstone, is also in igneous rocks like granite, and can be found in metamorphic rocks, too |
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Topaz |
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November's birthstone, Emerald and aquamarine are varieties of beryl, found in granites, can be found as pebbles in streams, used as a gemstone, to make a pink topaz, it must be heated, most blue topaz that is used for jewelry has been irradiated |
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Corundum |
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Sapphire and ruby are varieties of corundum, twice as hard as topaz, the second hardest natural mineral, used as gems, also in making watches and as an abrasive |
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Diamond |
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Simply a form of carbon, just like charcoal or graphite, used in jewelry and cutting tools, four times as hard as corundum Today there are new materials harder than diamonds but they are man-made. |
Other
examples: |
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