Minerals•***A mineral is a naturally occurring, inorganic, solid with a crystalline structure and a consistent

chemical composition***.

Biotite

The 5 Characteristics of a Mineral•Naturally occurring - can’t be man made (no

synthetics such as cubic zirconium)

•Inorganic - not made from living organisms

•Solid - No molten rock

5 Characteristics Continued…

•Crystal Structure - elements arrange in a regular and predictable pattern.

•Chemical composition - minor variations allowed

3-D Structure of a diamond

Fundamental Atomic Theory

• Elements cannot be broken down by chemical processes.

• Atoms are the basic component of an element.

• Atoms are composed of a nucleus containing protons and neutrons, with an electron cloud surrounding.

Fundamental Atomic Theory cont...

• Ions: Atoms that have lost or gained an electron and are now charged.

• Cation: Lost an electron, positive (+) charge.• Anion: Gained an electron, negative (-) charge.• Minerals form by combinations of atoms and ions

held together by bonds.

Halite - rock salt

Mineral Identification• Physical Properties: Run tests on the

physical characteristics of the sample.

• Crystal Structure: Shape of the sample.

• Chemical Properties: Reaction to acid, taste, or smell.

$40000.00 Diamond Studded IPod Shuffle.

Physical Properties

• Luster: How the mineral reflects light.

• Is it Metallic (M), or Nonmetallic (NM)?

Physical Properties cont.

• Hardness: Resistance to abrasion.

• Moh’s Hardness Scale• 1 - softest mineral (talc)• 10 - hardest mineral (diamond)• Fingernail - 2.5• Penny - 3.5• Glass - 5.5• Steel Nail - 5.5• Streak plate - 6.5

Breakage• Does the mineral break along flat surfaces?

No - uneven breakage, Fracture (F)

(ex. Quartz)

Yes - mineral splits along parallel planes, Cleavage ( C )

(ex. Halite)

Phys. Properties Cont.• Streak: Color in powdered form.

– Scrape the sample across the streak plate, what color is left behind?

• Specific Gravity (density): Weight of the mineral compared to an equal volume of water.

• Color: LEAST RELIABLE physical property.

Crystal Shape• The arrangement of ions in the atomic

structure determines the crystal shape.

Isometric

Ex. Pyrite

Hexagonal

Ex. Corundum

Trigonal

Ex. Hematite

Tetragonal

Ex. Zircon

Crystal Shape cont.

Orthorhombic

Ex. Topaz

Monoclinic

Ex. KunziteTriclinic

Ex. Amazonite

Other Properties…

• Magnetism

• Taste

• Odor

• Feel

• Reaction to acid

• Refracts Light

Rock Forming Minerals

• Silicates are the largest group of minerals.

• Make up 95% of the Earth’s crust.

• Contain silicon and oxygen.• Silicon - Oxygen tetrahedron,

SiO4

– Each Si is surrounded by 4 Oxygen

– Strong bonds, high hardness.

Important silicate minerals

• Feldspars: 50% of Earth’s crust• Quartz: Abundant in Continental crust• Pyroxenes and Amphiboles• Micas• Olivine: Rare in Continental crust

Ore Minerals: Mined for metals or other materials

Gems: Used for their looks. Example) Jewellery