Chapter 1: Minerals of the Earth’s Crust

Chapter 1:

Minerals of the Earth’s

Crust

What is a Mineral?A Mineral has 4 Characteristics:1. Solid2. Crystalline Structure3. Non-Living4. Formed by Nature (not man

made)

What is a Mineral Made out of?Atoms - smallest particle that can exist of a

substanceElements - a pure substance that cannot

easily be broken down

Compounds - different elements combine to form larger substances

Crystals - solid, geometric forms of minerals created by a repeating

pattern of atoms Minerals

Examples of Minerals

Most minerals can be classified based

upon their chemical composition (the

chemicals that make them up)

Composition of Minerals

• Minerals can be divided into 2 major groups:

1. Silicate minerals 2. Nonsilicate minerals

MINERALS

• Made of silicon and oxygen• 90% of Earth’s crust

Examples:–Feldspars –Biotite Mica–Quartz

SILICATE MINERALS

• Do not contain silicon and oxygenExamples include: •Copper•Gold•Silver

NONSILICATE MINERALS

Identifying Minerals

• Color• Luster• Streak• Cleavage• Fracture• Hardness – Mohs’ Scale 1-10, talc-

diamond• Density• Special Characteristics

Minerals can be identified by theircharacteristics.

• Minerals come in a variety of colors.

• Some colors are due to factors such as impurities and weather conditions.

1.) Color

Amethyst

1.) Color

2. Luster• The way a mineral reflects the

light. A mineral’s luster can be:

– Metallic (shiny)– Submetallic (a little shiny)– Nonmetallic (dull) – Vitreous (glassy)– Pearly (opalescent)

Metallic mineral

Semi-Metallic Mineral

Non-Metallic Minerals

3.) Streak• This is the color a mineral

appears when it is rubbed against an unglazed piece of porcelain

Streak Test

• The way that a mineral breaks. • Some break into

flat sheets, such as Mica• Others break in

angles, such as diamonds

4.) Cleavage

5.) Fracture• The tendency of some minerals to break unevenly along curved or irregular surfaces

• This is a mineral’s resistance to being scratched.

• Some minerals can be scratched easily, such as talc, while others are nearly impossible to scratch , such as diamonds.

6.) Hardness

7.) Density• This is how much matter is in a given

space. • Mineral density varies• Example:

•Gold’s density is much greater than mica’s.

Some minerals can be identified by othercharacteristics such as:• Fluorescence – glow under UV light• Chemical reaction – Fizzing when combined

w/acid• Optical Properties – Calcite will cause double

images• Radioactivity – Contain radium or uranium• Magnetism- attract iron• Taste – Salty, bitter, sour

8.) Special Properties

Fluorescence

Mining• Ore - Large enough deposit of an

element to gain a profit.

2 Types of Mining1.) Surface Mining• Removal of minerals or other materials at or

near the Earth’s surface. Examples: – Open pits– Strip mines– Quarries

• Materials mined in this way include copper ores and bauxite.

Open Pit

Strip Mine

2 Types of Mining2.) Deep Mining (Subsurface)• Drilling deep passageways below

Earth’s surface to reach the ore.

• Diamonds and coal are mined this way. – Can be VERY DANGEROUS!!!!

Deep Mining (Subsurface)

Responsible Mining•Mining can disturb habitats of plants and animals.•Waste products from the removal of the ore can also cause pollution.

Reclamation• Reclamation – law since 1970 states that after

mining you must return land to its original state after the mining is completed.

• Reduces potential harmful effects of mining.• Very expensive and time consuming!• Mining gives us the minerals we need, but it

also creates problems.– The waste products from a mine can get into water

sources, polluting both surface water and ground water.

RECAPWhat are the 4 characteristics of a

mineral?• Solid, Crystalline Structure, Non-Living,

Formed by NatureWhat are the two groups that minerals aredivided into?• Silicate and NonsilicateWhat are the 3 silicate minerals?• Feldspars, Biotite Mica, QuartzWhat % of Earth’s crust contains silicate

minerals?• 90%