Rocks & Minerals

Physical properties• See, hear, touch, taste, smell

• Density D = Mass ÷ Volume

• Hardness

• What it is made of

Minerals Are:* Solid, inorganic

materials that form naturally on or beneath

the Earth’s surface.

•Naturally Occurring – not man-made.

• Inorganic – not made from living things.

Identify Minerals

•Look at the Properties – characteristics that make one mineral different from other minerals.

Ways to Identify:•Hardness•Color•Streak•Luster•Cleavage•Density

Hardness

• Mohs Hardness Scale

• Ranks minerals from 1 (soft) to 10 (hard)

• 1 –Talc: flakes off w/ fingernail• 2- Gypsum: scratches w/ fingernail• 3 – Calcite: scratch w/ penny• 4 – Fluorite: easy to scratch w/ steel nail• 5 – Apatite: scratch w/ steel nail• 6 – Feldspar: it scratches glass• 7 – Quartz: can scratch steel & glass easily• 8 – Topaz: can scratch Quartz• 9 – Corundum: can scratch Topaz• 10 – Diamond: can scratch all other minerals

Color

• Not good to use.

• Several minerals come in different colors.

Streak

• Color of a mineral’s powder.

• Rub the mineral on a “streak plate”

Luster

• How a mineral reflects light.

• Glassy, pearly, silky, metallic, earthy

Cleavage & Fracture

•Cleavage: split apart easily along flat surfaces.

•Fracture: irregular surface where it breaks

Density• How much mass is contained in a given volume

• D = M ÷ V

Other Properties:• Chemical reaction: fizzes with vinegar (Calcite)

• Transparent – can see through it

• Opaque – pearly, cloudy

• Magnetic * High Mass