What is a Mineral

What is a Mineral?

• A mineral is a naturally occurring, inorganic solid with a specific chemical composition and a definite crystalline structure.

Characteristics of a Mineral

1. Solid

2. Naturally occurring

3. Inorganic (not made by living things)

4. Definite chemical composition

5. Definite crystal structure.

Crystal Systems

• There are six crystal systems:

1. Cubic

2. Tetragonal

3. Hexagonal

4. Orthrombic

5. Monoclinic

6. Triclinic

Ways that minerals can form

• Minerals can form in one of two ways:

1. From magma

2. From a solution

Minerals from Magma

• Magma is the molten or melted material found beneath Earth’s surface.

• Differences in density will force some magma up toward the Earth’s surface.

Minerals from Magma Continued

• If the magma cools quickly, the mineral crystals will be small.

• If the magma cools slowly, the mineral crystals will be large.

Minerals from Solutions

• Minerals can form from solutions in one of two different ways:

1. Crystallization from a supersaturated solution.

2. Evaporation of liquid from a supersaturated solution.

Mineral Groups

• There are about 3000 minerals that can be found in the Earth’s crust.

• Only 30 of these minerals are common.

• Most common minerals are referred to as rock forming minerals.

Mineral Groups Continued

• Most of the minerals found in the Earth’s crust are made of 8 common elements

1. O 5. Ca

2. Si 6. Na

3. Al 7. K

4. Fe 8. Mg

Mineral Groups Continued

• The mineral groups we will concentrate on in this class are as follows:

1. Silicates2. Carbonates3. Oxides4. Sulfides5. Sulfates6. Halides7. Native Elements

Silicates

• Silicates are compounds that contain silicon and oxygen.

• Make up approximately 96% of the minerals found.

• Feldspar and Quartz are silicates.

Carbonates

• Carbonates are minerals composed of one or more metallic elements with carbonate.

• Carbonate = CO3

• Calcite, dolomite and rhodochrosite are carbonates.

Carbonates Continued

• Carbonates are the primary minerals find in rocks such as limestone, coquina, and marble.

Oxides

• Oxides are compounds of oxygen and a metal.

• Hematite and Magnetite are common iron oxides.

Sulfides

• Sulfides contain sulfur plus one or more other elements.

• Pyrite is an example of a sulfide.

Sulfates

• Sulfates contain the compound sulfate.

• Sulfate = SO4

• Anhydrite is an example of a sulfate.

Halides

• Halides are made up of chloride or fluoride combined with calcium, sodium or potassium.

• Halite is an example of a halide.

Native element minerals

• Native element minerals are made up of one element only.

• Silver and Copper are examples of native element minerals.