MINERALS

What is a Mineral A naturally occurring, inorganic solid that has a definite chemical composition and crystal shape

Where do Minerals Come from? Come from magma. The rate of cooling determines the size. Cools Slow – Large crystals Cools Fast – Small Crystals

Minerals make up rocks

Minerals are grouped according to their chemical composition

How do we identify Minerals? ColorDensity LusterCrystal Shape HardnessStreak Cleavage or Fracture

Color Not reliable – change color

Luster The way the mineral reflects light Metallic/Non-metallic, Glassy, Silky

Hardness The ability of a mineral to resist being scratched

Hardness is measured with Moh’s Hardness Scale = Talc (powdery) 2.5 Fingernail 3.5 Penny10=Diamond 5.5 Glass 7 Topaz

Streak The color of the powder left by a mineral when rubbed against hard surface

Density Mass per volume D = M/V Most accurate way to identify mineral

Shape Result from the way the atoms or molecules of a mineral come together as mineral is forming

Fracture/Cleavage The way a mineral breaks Fracture = Uneven, rough jagged Cleavage = Smooth break