Chapter 2

Chapter 2 Minerals Reading: 2.1-2.6

Relationships to Earth Systems

• Biosphere• Hydrosphere• Atmosphere• Lithosphere

1) Calcite Limestone,2) Halite,3) Clay minerals

2.1 What is a Mineral?

• A mineral is a naturally occurring, inorganic solid, with a definite chemical composition and crystalline structure.

Is Ice a Mineral?• According to our definition?• Naturally occurring? • Inorganic? Solid?• Chemical composition ?• Crystalline structure?

2.2 Chemical Composition • First lets go to Atoms !• All matter is made of Atoms.• Every speck of Gas, liquid, or

Solid surrounding you is a mix of millions of Atoms.

Atoms and Elements

“The Big 8” Most Abundant Elements in Earth Crust

Charging Particles: Ions Positive Charge +

Cation(1-8)

Negative Charge –Anion(1-4)

Other Bonds

• Covalent BondBetween 2 Nonmetals neither one donates or gives up an electron, They simply Share in outer orbital shell forming Covalent bond

• Metallic Bond very few electrons in the outer most electron shells. Instead of donating or sharing these electrons are released from the orbital shell and available for a nearby cluster of atoms to use. “floting in a sea of Electrons”

Formulating Compounds

• SiO2

• (Mg, Fe)2SiO4

2.3 Crystalline Nature of Minerals• A crystal is any substance whose atoms are

arrange in a regular, periodically repeated pattern.

• When atoms combine to form minerals they so in organized way that forms a geometric pattern called crystal.

Crystals

Minerals and Rocks

• Room 222 ( Geology Building).

• Geology Building lobby

• Museum ?

Physical Properties of Minerals

1 Crystal habit (shape) 2) Cleavage & fracture 3) Hardness 4) Specific gravity 5) Color 6) Streak 7) Luster Others (Taste, Reaction to Acid, magnetism. )

Crystal Habit

Quartz: elongated crystals Quartz: no characteristic shape

Cleavage & Fracture

Mohs Mineral Hardness Scale

Specific GravityQuartz 2.7

Au 19

Color

Luster

Other

Mineral Classes

Silicates

Si

O

OO

O

Carbonates

2.6 Commercially Important Minerals

Important Minerals

2.7 Harmful and Dangerous Roks and Minerals

• Asbestos.

• Feldspar Quartz

Next Class

• Rocks