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