Chapter 13
Minerals of the Earth's Crust
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Vocabulary:
Mineral
Luster
Ore
Element
Streak
Reclamation
Compound
Cleavage
Crystal
Fracture
Silicate mineral
Hardness
Nonsilicate
Density
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Section 1 What is a Mineral?
Mineral- is a naturally formed, inorganic solid
that had defiant crystalline structure.
How to know if something is a mineral:
1)
2)
3)
4)
Has to be nonliving.
Has to be solid.
Has crystalline structure.
Must be nature made.
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Minerals are made from elements or groups of
elements.
Element- a substance that cannot be separated or
broken down into a simpler substance by chemical
means. (single Lego block)
Compound- a substance made up of atoms of two or
more different elements joined by chemical bonds.
(lots of legos)
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Crystals
Crystals- a solid whose atoms, ions, or
molecules are arranged in a definite pattern.
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Two GROUPS of Minerals
Silicates- a mineral that contains a combination
of silicon, oxygen, and one or more element.
Silicates make up 90% of the Earth’s crust.
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Two GROUPS of Minerals
Non- Silicates- a mineral compound that does
NOT contain compounds of silicon and
oxygen.
Non-silicates can contain oxygen and other
elements but do not contain silicon.
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Section 2 Identifying Minerals
Geologists use several ways to identify
minerals.
We will learn the 7 most common ways to
identify minerals by their characteristics.
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1. Color
We can identify minerals by color. This is not a
real good way because air, water, and
impurities can affect color.
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2. Luster
Luster- is the way a surface reflects light.
Shiny minerals usually have
a metallic luster.
Dull minerals usually
have a nonmetallic luster.
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3. Streak
Streak-The color of the powder of a mineral.
The streak can be found by rubbing a mineral
on a streak plate.
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4. Cleavage and Fracture
Cleavage- the splitting of a mineral along smooth,
flat surfaces.
Fracture- the manner in which a mineral breaks
along either curved or irregular surfaces.
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5. Hardness
Hardness- the measure of the ability of a
mineral to resist scratching.
Mohs Hardness Scale ranks mineral’s hardness
from 1 (soft) to 10 (hard).
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6. Density
Density- the ratio of the mass of a substance to
the volume of a substance.
Specific Gravity is the ratio of the mineral’s
density to the density of water.
Ex. Water has a density of 1 g/cm3. Gold has a density
of 19 g/cm3. To get gold’s Specific Gravity SIMPLY
DROP THE UNITS!
Gold’s Specific Gravity is 19.
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7. Special Properties
Some minerals can be identified by special properties
such as:
Fluorescence - Glow under a black light.
Chemical Reaction - Some minerals will “Fizz”
when you put acid on them.
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7. Special Properties
Optical Properties - some minerals will act like a
magnifying glass.
Magnetism - Some minerals are magnetic.
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7. Special Properties
Taste- Some minerals will taste salty.
Radioactivity- Some minerals are RADIOACTIVE!!
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Section 3 The Formation, Mining, and
Use of Minerals
What we will learn in this section:
1. Describe the environments in which minerals
will form.
2. Compare the two types of mining.
3. Describe two ways to reduce the effects of
mining.
4. Describe different uses for metallic and nonmetallic minerals.
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Mining
Mining is the process of getting ore out of the
ground.
Ore— a natural material whose concentration of
economically valuable mineral is high enough
for the material to be mined profitably.
Mining can be done inside the earth and on the
surface.
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Types of Surface Mining
1) Surface Mining—where minerals are dug up close to the
surface of the Earth.
Types of surface mining include:
• Open Pit Mining—used to remove large, near-surface
deposits of economically important minerals. Ex. gold, copper.
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• Quarry—open pits used to mine building
stone, crushed rock, sand and gravel.
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• Surface Strip Mining— coal is removed in
strips.
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Underground Mining
2. Subsurface Mining—minerals deep in the
Earth are dug out using horizontal passage
ways or a vertical shafts.
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Effects of Mining
• Mining gives us mineral we need, but it creates
problems.
• Reclamation—process of returning land to its
original condition after mining is complete.
• Reclamation has been required by law since the
1970s.
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The Uses
of Minerals
• Metallic Minerals- are good conductors of
heat and electricity.
• Used in airplanes, cars, computers, and other
electronic devices.
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The Uses of Minerals
• Non-Metallic Minerals- are good insulators of
electricity and building products.
• Used in concrete, drywall, toothpaste,
glassmaking, etc.
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The Uses of Minerals
• Gemstones are highly valued for their beauty
and rarity rather than their usefulness.
• Used in rings, necklaces, bracelets, and other
jewelry.
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