Minerals & Rocks Study Guide
Minerals (pages 44-52 of textbook)
Mineral characteristics:
N – Naturally occurring
I - Inorganic
S - Solid
C - Crystalline structure
D – Definite Chemical Composition
Inorganic- not made from anything that is alive or has ever been alive.
Crystal – repeating pattern of a minerals particles
Streak – the color of the powder of a mineral
Moh’s Hardness Scale – Scale ranking minerals by hardness 1-10. 1 is
softest (Talc) 10 is hardest (diamond)
Luster – How light reflects from a mineral’s surface.
Density – mass divided by volume m/v
Cleavage – break of mineral along a flat surface
Fracture – break of a mineral in an irregular way
Minerals are identified by:
1. Color
2. Streak
3. Luster
4. Density
5. Hardness
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Minerals & Rocks Study Guide
6. Special properties (magnetism, glowing under ultraviolet light,
doubles images, reaction to acids)
Rocks
(pages 54-72)
Rocks are made up of minerals, soil, and sometimes even organic materials.
Geologist study a rock’s mineral composition (what minerals are in it), color and
texture (the look and feel of its surface which is a result of the size and shape of
its grains-particles).
Rock forming minerals – common minerals that make up most of the rocks on the
Earth.
Rocks are classified by how they are formed. There are 3 classifications of rocks:
igneous, sedimentary and metamorphic.
1. Igneous rocks
 Formed from cooling of molten rock
 Classified by origin (where they form),texture, and minerals
composition
 Intrusive igneous rocks- cool inside the earth’s surface (larger
grained crystals)
 Extrusive igneous rocks – cool outside the earth’s surface(smaller
grained crystals)
 Igneous rocks that are have very little Silica (oxygen and silicon
mixture) are lighter in color than those with more silica.
 Basalt is a darker igneous rock that usually found in or on oceanic
crust.
 Granite is lighter colored igneous rock that is usually found in or on
continental crust.
2. Sedimentary rocks
 Formed from Deposition, Compaction and Cementation of sediments
(small pieces of rocks and soil)
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Minerals & Rocks Study Guide
 Clastic sedimentary rocks – formed when rock pieces are squeezed
together
 Organic sedimentary rocks – formed when remains of plants and animals
are deposited in thick layers
 Chemical sedimentary rocks – formed when minerals are dissolved in a
solution and crystalize
3. Metamorphic rocks

Formed when sedimentary or igneous rocks are under extreme heat
and pressure deep underneath the Earth’s surface.



Foliated – grains arranged in parallel layers and bands
Non-foliated – grains arranged randomly
Common metamorphic rocks that from by heat and pressure from
other rocks are:
- Granite (igneous) changes to Gneiss (metamorphic)
-
Igneous Rock
(Magma cooling)
Sandstone(sedimentary) changes to Quartzite (metamorphic)
Shale (sedimentary) changes to Slate(metamorphic)
Sedimentary Rock
(Deposition, compaction
Metamorphic Rock
(heat & pressure)
& cementation)
Types
Types
Types
Non-
Intrusive
Extrusive
Clastic
Organic
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Chemical
Foliated
Foliated
Minerals & Rocks Study Guide
Rocks are broken down by:
1. Melting - heat turns rocks into liquid molten rock called magma
2. Weathering - wearing down of a rock turning it back into sediment
Mechanical weathering--- rocks physically broken
Chemical weathering ---breaking down of rock by a chemical
changes
3. Erosion – the movement of rocks and soil caused .by humans, animals, or
weather.
.
Rock Cycle: a slow process that builds, destroys and changes rocks. It can
change rocks from one kind to another kind of rock.
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