MINERAL IDENTIFICATION

Minerals

• What is a mineral? Naturally occurring (not man-made)

Inorganic (not part of or a product of a (once)living organism )

Solid (not made of liquid or gas) with a definitechemical structure which give it uniquephysical properties.

Minerals• What is a mineral?

Naturally occurring (not man-made)

Inorganic (not part of or a product of a (once) living organism )

Solid (not made of liquid or gas)

Specific chemical composition(molecular formula)

Definite crystalline structure

Minerals have Physical Properties based on the

INTERNAL ARRANGEMENT OF ATOMS

&

CHEMICAL COMPOSITION

Most Minerals can be identified by inspection and or by simple tests.

Mineral Identification Tests Color Hardness Streak Luster Density Specific Gravity and Known Unique Properties

Colorfor some minerals color is directly related to the

compositionColor is the least

diagnostic property

Lusterappearance of a mineral in

reflected lightA mineral that shines like a metal has metallic luster

A mineral that transmits the light has a nonmetallic luster

TextureHow a mineral feels to the

touch.Examples: smooth, greasy, silky, ragged, rough, soapy,

and glassy

StreakColor of finely powdered mineral.The streak color and mineral color are not always identical. The streak color is typically constant for a given mineral.

Hardnesshow easily a mineral can

be scratchedmeasured using Mohs

hardness scale (what can scratch what)

MohsMohs hardness scale hardness scale

Hardest

10. Diamond 4. Fluorite

9. Corundum 3. Calcite

8. Topaz 2. Gypsum

7. Quartz 1. Talc

6. Potassium Feldspar Softest

5. Apatite

Reference Materials

--fingernail at 2.5 --old penny (copper) at 3.5 --window glass or typical

knife blade 5.5 --porcelain plate or good steel

file 7.5

Absolute Hardness1 Talc 72 Orthoclase 3 Gypsum 100 Quartz 9 Calcite 200 Topaz 21 Fluorite 400 Corundum 48 Apatite 1600 Diamond

Cleavage and FractureInternal Arrangement of

Atoms determines how a mineral will break

Cleavage- repeatable breaks along definite plane surfaces, At least one Flat Side

Fracture- uneven non repeated breaks,

All rough Sides

DensityMinerals have a constant

density

Impurities in your sample may cause the density to

vary slightly

Specific GravityWeightair

(Weightair - Weightwater)

Known Unique Properties

Examples Acid Test

Refraction/Reflection of LightMagnetic Properties

Acid TestCalcite (CaCo3) bubbles

(reacts) when dilute hydrochloric acid (HCL) is dropped on its surface