Download What is a mineral?

What is a mineral?
Objectives
• Define a mineral.
• Describe how minerals form.
• Identify the most common elements in Earth’s crust.
What is a mineral?
What is a mineral?
• Earth’s crust is composed of about 3000
minerals.
• Minerals form rocks and shape Earth’s surface.
• Some have played a role in shaping civilization.
What is a mineral?
Mineral Characteristics
• A mineral is a
naturally occurring,
inorganic solid with
a specific chemical
composition and a
definite crystalline
structure.
What is a mineral?
Mineral Characteristics
Naturally Occurring and Inorganic
– they are formed by natural processes.
– they aren’t alive and never were.
What is a mineral?
Mineral Characteristics
Solids with Specific Compositions
– All minerals are solids .
– Unique chemical composition.
– Vast majority are made from compounds.
Fe2O3
SiO4
NaCl
What is a mineral?
Mineral Characteristics
Definite Crystalline Structure
– A crystal is a solid in which the atoms are arranged
in repeating patterns.
Tetragonal
Cubic
Triclinic
Orthorhombic
Hexagonal
Monoclinic
What is a mineral?
Mineral Characteristics
Definite Crystalline Structure
Cubic
What is a mineral?
Mineral Characteristics
Definite Crystalline Structure
What is a mineral?
Minerals From Magma
• Magma is molten material found beneath Earth’s
surface.
• Rapidly cooling magma = Small crystals
• Slowly cooling magma = Large crystals
What is a mineral?
Minerals From Magma
What is a mineral?
Minerals from Solution
• Saturated: a
solution holds as
much solute as
possible (filled-up)
– Precipitation: solids form out of
saturated solutions.
– Evaporation: elements left behind
arrange into crystals (evaporites).
What is a mineral?
Mineral Groups
• About 30 minerals are common in Earth’s crust.
• These are mostly the rock-forming minerals.
• Vast majority of minerals are made up of only
eight common elements.
What is a mineral?
Mineral Groups
What is a mineral?
Mineral Groups
Silicates
– Silicates are minerals that contain silicon and
oxygen, and usually one or more other elements.
– 96 percent of the minerals in Earth’s crust.
– Most common minerals: feldspar and quartz
What is a mineral?
Mineral Groups
Carbonates
– One or more metallic elements + the carbonate ion, CO3.
– limestone, coquina, and marble. (calcium carbonate)
What is a mineral?
Mineral Groups
Oxides
– Oxides are compounds of oxygen and a metal.
– Hematite (Fe2O3) and magnetite (Fe3O4) are
common iron oxides and good sources of iron.
What is a mineral?
Mineral Groups
What is a mineral?
Section Assessment
1. Match the following terms with their definitions.
___
B mineral
___
C crystal
___
D magma
___
A silicate
A. minerals that contain silicon and
oxygen, and usually one or more
other elements
B. a naturally occurring, inorganic solid
with a specific chemical composition
and definite crystalline structure
C. a solid in which the atoms are
arranged in repeating patterns
D. molten material found beneath
Earth’s surface
What is a mineral?
Section Assessment
2. What are the two ways that minerals can form
from a supersaturated solution?
Mineral crystals can precipitate, or drop out of
solution if the solution becomes supersaturated.
Minerals can also form when liquid evaporates
from a supersaturated solution leaving behind
the elements which may begin to arrange
into crystals.
What is a mineral?
Section Assessment
3. Identify whether the following statements are
true or false.
_______
true
There are about 30 common minerals in
Earth’s crust.
_______
false Slowly cooling magma produces small crystals.
_______
false Coal is a mineral.
_______
true
Silicates are the most common minerals
on Earth.
_______
true
Well-defined crystal shapes are rare.
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