What Is A Mineral?

Characteristics and properties used to identify minerals.

What are characteristics of minerals?

Solid Formed in nature Non-living Crystalline structure

Particles line up in a repeating pattern

What are the Six Physical Properties of Minerals?

Used to identify all minerals

1. Color

The surface color of the mineral Minerals come in a variety of colors

Examples of Mineral Colors

2. Luster

The way a surface reflects light.

(glassy, metallic, waxy, shiny, etc.)

Examples of Luster

MetallicLooks like metal

PearlyLooks like a pearl

Vitreous/GlassyLooks like glass

DullNon-

reflective

ResinousLook of dried

glue

EarthyLooks like dried mud

3. Streak

The color of the mineral in powdered form. Streak color and mineral color are often

different. Examples: Hematite – brick red Galena – steel gray Pyrite – brassy yellow or black Olivine – white Feldspar – white Talc – white Gypsum – colorless

Examples of Streak

4. Cleavage & Fracture

Cleavage = tendency of minerals to break along a flat surface.

Fracture = tendency of minerals to break unevenly along a curved or irregular surface

Examples of Cleavage

Cube or cubic

Octahedronor Octahedral

Pinacoid –2 parallel faces

PrismPyramid

Dome

Examples of Fracture

Subconchoidal Uneven

Jagged Splintery Earthy

Conchoidal

5. Hardness

A mineral’s resistance to being scratched. Any mineral with a higher hardness rating can

scratch a mineral with a lower hardness rating.

Diamond is the hardest natural substance known to humans.

Moh’s Hardness Scale1. Talc 2. Gypsum

--fingernail at 2.5 3. Calcite

--copper (old penny) at 3.5 4. Fluorite 5. Apatite

--window glass or typical knife blade at under 5.5 6. Orthoclase

--streak plate or good steel file at over 6.5 7. Quartz 8. Topaz 9. Corundum 10. Diamond

6. Density

How much matter there is in a given amount of space.

Galena – specific gravity = 7.4 to 7.6

What are some Special Properties?

Fluorescence Magnetism Light refraction

Taste Odor

What are some uses of minerals?

Coins Jewelry Electrical wires Batteries Paint Steel Building materials etc.

Rocks are made out of minerals, but minerals are

not made of rocks.