MINERALSChapter 3

Section 1What is it?

1. Naturally occurring- formed by processes on or outside Earth with NO input from humans

2. Inorganic- Not made by life processes3. Element or Compound with a definite chemical

compositionEX: Halite (NaCl): (salt) distinctive taste that adds flavor to food

4. Orderly arrangement of atoms- All minerals are crystalline solids (Definite shape and volume)

STRUCTURECrystal - solid with atoms arranged in orderly, repeating

patterns1. Some form from magma hot melted rock below

the Earth’s surfaceWhen magma cools:

* Slowly large crystals* Quickly small crystals

2. Can form from solutions- Water evaporating- Too much of a substance is dissolved in water (H₂O)

Mineral Composition and Groups

Groups are defined by their composition (What they’re made up of)

1. Silicates (Most common): Contain silicon (Si), Oxygen (O), and 1 or more other elementsEX: Quartz and Feldspar

2. Silicon (Si) and Oxygen (O) are the 2 most abundant elements in Earth’s crust.- They form the building blocks of many minerals in Earth’s crust and mantle

Glue in Crystal Shapes

EX:Cubic Fluorite: Equal in size along all 3 dimensionsTetragonal Nickel: Longer on dimensions and

shorter on the other (Rectangular)Hexagonal Quartz: 6 long sides, 2 facesOrthorhombic Sulfur: Dimensions are unequal in

length (Brick-like)Monoclinic Gypsum: Unequal dimensions, 1 right

angle, some oblique anglesTriclinic Copper sulfate: Least amount of symmetry,

unequal on ALL sides

MINERAL IDENTIFICATIONSection 2: Physical Properties

Color and appearance are NOT enough to distinguish most minerals

1. Hardness- measure of how easily a mineral can be scratched- Mohs Scale compares minerals hardness

GLUE IN MOHS SCALE

2. Luster- The way a mineral reflects light- Can be metallic (shinny metal) or nonmetallic (NOT shinny) - Nonmetallic lusters include: dull, pearly, silky, glassyEX: Quartz, calcite, halite, fluorite

3. Streak- The color of a mineral in powered form- Only useful if mineral is softer than a streak plateEX: Your pencil Graphite leaves streak on your paper

4. How do mineral break?Cleavage- break along smooth, flat surfaces

EX: Mica, halite Fracture- Breaks with uneven, rough, or

jagged surfacesEX: Quartz

5. Some minerals have unique properties involving light or magnesium

USES OF MINERALSSection 3

1. Gems- rare and beautiful minerals that are highly prized- Famous historical gems Cullinan diamond

Hope diamond- Some have industrial applications in abrasive, lasers, and electronicsEX: Rubies – produce specific types of laser light

Quartz – electronics and time pieces (watches)

2. Useful elements in mineralsOre- a mineral or rock containing a substance that

can be mined at a profitElements must be refined (purified) from ores

(Separating out unwanted materials)Some elements dissolve in fluids, travel through

weaknesses in rocks, and in those weaknesses form deposits called vein mineral deposits.

Titanium- useful element derived(made from) from the minerals ilmenite and rutile- Used for: golf clubs, racing bikes, cars, wheelchairs, ect.