Minerals

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

Mineral formation

Magma crystals from solution

Mineral Composition Groups

Silicates: contain silicon and oxygen

Mineral Identification(physical properties)

Appearance Hardness Luster Color Streak

Cleavage vs Fracture

Appearance

What does the mineral look like?

Hardness

How easily a mineral can be scratched Mohs Hardness scale

Mohs Hardness Scale

Softest Hardness of Common Objects

Talc 1

Gypsum 2 fingernail (2.5)

Calcite 3 piece of copper (3.5)

Fluorite 4 iron nail (4.5)

Apatite 5 glass (5.5)

Feldspar 6 steel file (6.5)

Quartz 7 streak plate (7)

Topaz 8

Corundum 9

Diamond 10

Hardest

Luster

How light reflects off the surface of a mineral. Examples: metallic, dull, pearly, glassy, silky

Color

The color of the mineral.

Streak

The color of a mineral when it is powdered. Use streak with metallic minerals.

Hematite

Cleavage vs Fracture

Cleavage is when a mineral breaks along a smooth flat surface.

If a mineral fractures the break is random or jagged.

Malachite(no-cleavage)

Mineral Identification

Luster: metal or nonmetal metals we streak test, then test hardness nonmetals we test hardness, starting with

glass: is the mineral harder or softer than glass

Use of Minerals

Gems: rare and beautiful minerals of value. Ores: contain useful minerals that can be

mined at a profit.