Minerals! What is a Mineral? A mineral is a naturally occurring, - - PDF document

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Minerals!

What is a Mineral?

• A mineral is a

naturally occurring, inorganic solid with a distinct crystalline structure and chemical composition.

• They are the building

blocks of rocks!

• There are 4,000

known minerals!

5 Characteristics

• 1. Naturally occurring
• 2. Solid substance
• 3. Orderly crystalline structure
• 4. Definite chemical composition
• 5. Inorganic(was never alive)

Naturally Occurring

• A mineral forms by natural geologic

processes meaning processes that occur

• n or inside Earth with no input from

humans.

• Synthetic gem, such as synthetic

diamonds and rubies, are not considered minerals.

Solid Substance

• Minerals are solids within the

temperature ranges that are normal for Earth’s surface.

Orderly Crystalline Structure

• Minerals are

crystalline substances which means that their atoms are arranged in a pattern that is repeated over and

• ver again.

Crystalline Structure?

How Minerals Form

4 major processes:

• 1. Crystallization from magma
• 2. Precipitation
• 3. Changes in pressure and temperature
• 4. Formation from hydrothermal

solutions

Properties of Minerals

• Color
• Streak
• Luster
• Hardness
• Breakage

Color

• Color is unique to some minerals.

However, this property is often not useful in identifying many minerals.

• Small amounts of different elements

can give the same mineral different colors.

Streak

• Streak is the color of a mineral in its

powered form.

• Streak is obtained by rubbing a mineral

across a streak plate, a piece of unglazed porcelain.

Luster

• Luster is used to describe how light is

reflected from the surface of a mineral.

• Luster can be described as either metallic
• r nonmetallic.
• Minerals with a metallic always shine like

metal.

• Minerals with a nonmetallic luster can be

described as glassy, pearly, silky, and earthy.

Metallic or Nonmetallic?

Hardness

• Hardness is a measure of the

resistance of a mineral to being

• scratched. You can find this property

by rubbing the mineral against another mineral of known hardness.

Mohs Hardness Scale

The Mohs Hardness Scale is a standard hardness scale used by

• geologists. It consists
• f 10 minerals

arranged from 10 (hardest) to 1 (softest).

Breakage

There are two ways minerals break.

• 1. Cleavage is the tendency of a mineral to

cleave, or break along smooth flat surfaces.

• 2. Fracture is the uneven breakage of a
• mineral. Minerals that do not show

cleavage when broken are said to fracture.

Cleavage or Fracture? Uses of Minerals

• Gems – a valuable

mineral highly prized because it is rare and beautiful

• Ores – a mineral

that contains a useful substance that can be mined at a profit.

– Aluminum – Iron