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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