By: Megan Tietz

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Rocks and Minerals

• By Megan Tietz

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What is a Mineral?

• A mineral is an inorganic naturally-occurring
  crystalline solid. It has specific physical
  properties and a definite chemical composition.

http//www.sdnhm.org/kids/minerals/faq.htmlminera
l
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What is a Rock?

• A rock is usually composed of 2 or more minerals
  in some physical combination, although some rocks
  are composed of only one mineral.

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Is a Rock a Mineral?

• No. Although a rock is also inorganic and occurs
  naturally, it is not a crystalline solid. It is a
  consolidated material composed of grains of one
  or more minerals .

http//www.sdnhm.org/kids/minerals/faq.htmlminera
l
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How are Rocks Formed

• There are three types of ways rocks are formed
• Sedimentary Rocks
• Igneous Rocks
• Metamorphic Rocks

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Sedimentary Rocks

• When rocky fragments and sediments are deposited
  together by wind, water or ice, they gradually
  (over thousands or more years) cement together
  into new rocks, called sedimentary rocks.
  Limestone and sandstone are common sedimentary
  rocks. You can often find fossils embedded in
  these rocksthey were deposited together with the
  sediments!
• http//www.childrensmuseum.org/geomysteries/faqs.h
  tml

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Limestone
Shale
Conglomerate
Gypsum
Sandstone
http//sln.fi.edu/fellows/payton/rocks/expert/gnei
ss.htm
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Igneous Rocks

• When molten rock called magma rises up from the
  earth's mantle deep underground, it forms igneous
  rocks. Some igneous rocks erupt from volcanoes as
  lava or pumice. Others, like granite, form in
  underground magma chambers.
• http//www.childrensmuseum.org/geomysteries/faqs.h
  tml

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Granite
Pumice
Obsidian
Scoria
http//sln.fi.edu/fellows/payton/rocks/expert/gnei
ss.htm
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Metamorphic Rocks

• Sometimes sedimentary and igneous rocks are
  changed dramatically by forces inside the Earth.
  Extreme heat or pressure underground can bake,
  squeeze, or fold rocks into something new. Then
  they are called metamorphic rocksmetamorphic is
  Greek for "change of form.
• http//www.childrensmuseum.org/geomysteries/faqs.
  html

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Schist
Gneiss
http//sln.fi.edu/fellows/payton/rocks/expert/gnei
ss.htm
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www.cotf.edu/ete/modules/msese/earthsysflr/rock.ht
ml
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Does the Rock Cycle Ever Stop?

• No, the rock cycle never stops. Rocks keep
  breaking down and into pieces and keep changing
  into other types of rocks. Its just one big
  cycle that keeps going and going

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All rock can be heated. But where does the heat
come from? Inside Earth there is heat from
pressure (push your hands together very hard and
feel the heat). There is heat from friction (rub
your hands together and feel the heat). There is
also heat from radioactive decay (the process
that gives us nuclear power plants that make
electricity). So, what does the heat do to the
rock? It bakes the rock.
Rocks and Heat
http//www.cotf.edu/ete/modules/msese/earthsysflr/
rock.html
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Properties of a Mineral

You can tell the differences between minerals by
looking for certain properties. Because each
mineral is unique both chemically and
structurally, each has its own set of physical,
optical, and structural properties which aid in
its identification.
http//rockhoundingar.com/pebblepups/basics.html
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What are the Physical Properties?

• Specific Gravity
• Streak
• Hardness
• Light Dependent properties
• Color
• Luster
• Diaphany

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Mohs Rock Hardness Scale
http//www.childrensmuseum.org/geomysteries/faqs.h
tml
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When can you start collecting?

• The best thing about starting a geology
  collection is that you get to collect a little
  bit of everything. After a while you'll discover
  what you're most interested in, and be able to
  concentrate on a certain area. For example, you
  may focus on collecting fossil shark teeth, or on
  fossils of the Cretaceous period, or even on
  minerals that are the color blue! You can look
  for rocks and minerals anywhere, even when you on
  family vacations or out at the park. Just make
  sure your in an area that its ok to take them.