1. Earth Science - Chapter 3
Minerals

2. Section 1 Minerals – Four properties
Naturally Occurring – Formed by processes on or inside the earth with no input from humans
Inorganic – not made by a life process
Defined Chemical Composition – Fixed make-up of elements or compounds
Atoms have an orderly arrangement which leads to the crystalline structure

3. Section 1… Continued
Crystal – Solid with atoms arranged in orderly, repeating patterns
Some crystals form from magma – a hot melted rock below the Earth’s surface
Slow Cooling – creates large crystals
Fast Cooling – creates small crystals
Example: Volcano erupts and on the slop of the hill you will have larger crystals forming in comparison to those cooled quickly by the sea

4. Slow vs Fast Cooling
Figure 2 A sample of rhyolite - the crystals are too small to see. (The colour banding was produced as the sticky lava flowed over the ground)
Figure 1 A sample of granite, note the large crystals

5. Crystals… Continued
Crystals can also be formed by solutions evaporating
Elements with in the solution form crystals as the volume of liquid is reduced
The dissolved particles form crystals as a result
Example: Rock Candy - sugar

6. Section 1… Continued
Mineral groups – have the same composition throughout
Silicates are the largest group of crystalline structures
Silicon and oxygen are the two most abundant elements in Earth’s crust; they form the building blocks of many minerals.

7. Section 2 – Mineral Identification
Color and Appearance are not enough information to distinguish one mineral from another
Hardness is a measure of how easily a mineral can be scratched; The Mohs scale compares minerals hardness
Softest – a fingernail scratch…Talc
Hardest – can not be scratched… Diamond

8. Section 2 - Continued The way a mineral reflects light is its luster
Can be metallic or nonmetallic
Nonmetallic lusters include
Dull
Pearly
Silky
Glassy
Specific Gravity is the ratio of the mineral’s weight to the weight of an equal volume of water.

9. Section 2 - Continued
Streak is the color of the mineral in powder form.
Note… the mineral must be softer than the porcelain plate that is used in the test
The way in which a mineral breaks apart can be a distinguishing characteristic.
Minerals with cleavage breaks along smooth, flat surfaces
Minerals with fracture break with uneven, rough, or jagged edges

10. Section 2 - Continued
Other minerals have very unique properties like how light passes through them or magnetism

11. Section 3 – Uses of Minerals
Gems are rare and beautiful minerals that are highly prized
The Hope diamond and the Cullinan diamond are famous historical gems
Gems also have industrial applications.
Abrasives
Lasers
Electronics

12. Section 3 - Continued
Minerals can be mined for the elements they contain
An ore is a mineral or rock containing a substance that can be mined for profit
Elements must be refined, or purified, from the ore
Elements that can be dissolved in liquids can sometimes travel to and pool in cracks of rocks. These are called veins .

13. Section 3 - Continued Mineral combinations are very helpful as well.
Titanium is a useful metal that comes from the combination of two minerals, ilmenite and rutile

14. Discussion Questions
How does the rate of evaporation effect crystal shape?
How does the rate of evaporation effect crystal size?
Name five properties that can be used to identify a mineral.
Besides jewelry, what are some other applications for minerals?