chapter 1: minerals of the earth’s crust. what is a mineral? a mineral has 4 characteristics:...

Chapter 1:

Minerals of the Earth’s

Crust

What is a Mineral?A Mineral has 4 Characteristics:

• Solid•Crystalline Structure•Non-Living• Formed by Nature (not man made)

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

substance

Elements - 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

• Most minerals can be classified based upon their chemical composition (the chemicals that make them up)

• Ex: Sodium (Na+) and Chlorine (Cl-) form a compound called Sodium Chloride (NaCl) which is a mineral called Halite or table salt.

• Minerals can be divided into 2 major groups:

1. silicate minerals 2. nonsilicate minerals

• Made of silicon and oxygen

• 90% of Earth’s crust

Examples:–Feldspars –Biotite Mica–Quartz

• Feldspars - Most abundant surface rock, made up about 50 to 60% of Earth’s crust

• Biotite Mica – Shiny & soft, separate into sheets when they break

• Quartz – Basic building block of many rocks, crystal looking

**Can one rock contain all of these minerals? YES or NO

• Do not contain silicon and oxygen

Examples include: • Native elements- (Copper, gold, silver, platinum,

diamond)•

• Carbonates- (cement & fireworks)

• Halides- (detergents)

• Oxides- (aircraft parts & paint)

• Sulfates – (cosmetics, toothpaste, paint)

• Sulfides- (batteries, medicine, electronics)

Identifying Minerals - Minerals can be

identified by…..their characteristics.• Color

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

• Density• Special Characteristics

• Minerals come in a variety of colors. Some colors are due to factors such as impurities and weather conditions.

Color

Amethyst

Luster

This is the way a mineral reflects thelight. 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

Streak• This is the color a mineral

appears when it is rubbed against an unglazed piece of porcelain

Streak Test

• Cleavage: this is the way that a mineral breaks.

• Some minerals break into flat sheets, such as Mica, while others break in angles, such as diamonds

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.

Hardness

Density

• This is how much matter is in a given space. • Mineral’s densities vary, for

example: gold’s density is much greater than that of mica

Some minerals have special properties.

Identified by other characteristics such as…..

1. Fluorescence – glow under UV light

2. Chemical reaction – Fizzing when combined w/acid

3. Optical Properties – Calcite will cause double images

4. Radioactivity – Contain radium or uranium

5. Magnetism- attract iron

6. Taste – Salty, bitter, sour

Fluorescence

Mining

• Large enough deposit of an element to gain a profit is called an ore.

2 Types of Mining

1.) Surface Mining• Removal of minerals or

other materials at or near the Earth’s surface.

• Types of surface mines include: – Open pits– Strip mines– Quarries

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

2.) 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!!!!

Products Made from Mining• MINERALMETALUSES

Mineral in

Ground

Metal turned

into

Product made

Chalcopyrite

copper coins, electrical wire

Galena lead batteries, paintBeryl beryllium bicycle frames,

airplanesChromite chromium stainless steel,

cast iron

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.

• Very expensive and time consuming!

• Mining gives us the minerals we need, but it also creates problems.

– Can destroy or disturb the habitats of plants & animals.

– The waste products from a mine can get into water sources, polluting both surface water and ground water.

RECAP