Chapter 3- Minerals

Section 1- Properties of Minerals

• Mineral= a naturally occurring, inorganic solid that has a crystal structure and a definite

chemical composition

5 Characteristics of Mineral

1. Naturally occurring- found in the natural world

- Not natural (plastic, steel, brick, concrete)

2. Inorganic= not formed from a living thing or once living thing

What is a Mineral?

What is a Mineral?

5 Characteristics cont…

3. Solid

4. Crystal Structure- Crystal= the repeating

pattern of a mineral’s particles

5. Definite chemical composition (make-up)= contain certain elements in a definite proportions

Identifying Minerals?

5 Tests for Identifying Minerals

1. Color

2. Streak color

- Streak= the color of a mineral’s powder

* Done by rubbing the mineral across a tile

Identifying Minerals?

5 Tests for Identifying Minerals cont.

3. Luster= measure of light reflected from a mineral’s surface - (Can be described as glassy, pearly, waxy,

silky, metallic)

4. Density= mass (weight) of an object in a given space

Density =

Identifying Minerals?5. Hardness

- Mohs hardness scale= a scale which ranks 10 minerals from softest to hardest

* Done by scratching the mineral with objects of varying hardness (Example:

fingernail=2)

Identifying Minerals?

• Minerals can also be identified by how they break apart.

2 Ways Minerals Break

1. Cleavage= when a mineral splits along a flat surface

2. Fracture= when a mineral breaks apart in an irregular way

Cleavage

Fracture

Section 2- How Minerals Form

How Minerals Form?

• Crystals form by crystallization= a process by which atoms are arranged to form a crystal structure

2 Methods of crystallization

1. Molten material

2. Materials dissolved in water

Cave of Crystals in Mexico

Minerals from Magma and Lava

• Magma= molten material from inside the earth that hardens to form a rock

• Lava= magma that reaches the surface

* When magma and lava cool they form crystals

• Rate of cooling determines crystal size

- Slow cooling large crystals (magma)

- Quick cooling small crystals (lava)

Minerals from Solutions

• Solution= mixture in which one substance is dissolved in another

- For example: Kool-aid in water

• Geode= a rounded hollowed out rock lined with mineral crystals

- Formed when water enters rockthrough a crack and elements

begin to crystallize on rock wallsGeode

Minerals from Solutions

• Minerals can also be formed from…

- Evaporation of a solutionleaving behind the minerals

- Hot water solutions

As hot water heated by magma begins to cool the elements in the water can escape and

crystallize in veins= a narrow channel of mineral that is different from the surrounding rock

Gypsum Rose

Gold Vein

Section 3- Using Mineral Resources

The Uses of Minerals

• Gemstone= a hard, colorful mineral that has a brilliant or glassy luster

(Ruby, Opal, Sapphire, diamond…)

- Jewelry, decoration, mechanical parts for grinding and polishing

• Metals (Aluminum, iron, copper, silver)

- Very ductile and malleable

- Building frames, cars, money, jewelry

The Uses of Minerals

• Other Uses (In foods, medicines, fertilizers and building materials)

- Talc talcum powder

- Quartz glass, electronic parts, and watches

- Gypsum wallboard, cement, and stucco

Rough Beginnings

• Minerals are obtained in the form of an ore= a rock that contains a metal or other useful mineral that can be mined and sold as a profit

Making Metals from Minerals

First they must be undergo…

- Prospecting- find the mineral

- Mining- dig up the mineral

- Smelting- melting down and removal of unwanted material from the wanted mineral

Making Metals from Minerals

• Further Processing

- Alloy= a solid mixture of a metal and one or more elements

Ex: iron + carbon= steel

*Why an alloy?

- Can give the metal better qualities (stronger, rust resistant, shinier)

Ex: Steel + manganese makes stronger steel