Minerals Are: * Solid, inorganic materials that form naturally on or beneath the Earth’s surface.

Have a definite chemical composition. Usually solid. High temp. inside the Earth can melt them.

Naturally Occurring – not man-made Naturally Occurring – not man-made. Formed as a result of processes in the natural world.

Inorganic – not made from things that were once alive.

Have definite crystal structure – repeating patterns of a mineral’s atoms.

Definite Chemical Composition – Each type of mineral has the same proportions of the same elements.

How Mineral Form Most minerals form when molten material (magma) cools and hardens inside Earth or on the surface Some form when a solution evaporates on Earth’s surface Ex. Halite NaCl

How Minerals are Formed If magma or lava cool slowly then large crystals will form Ex. Quartz If magma or lava cool quickly the small crystals will form Ex. Feldspar

Identify Minerals Look at the Properties – characteristics that make the mineral different from other minerals.

Ways to Identify: Hardness Color Streak Luster Cleavage Density

Identifying Minerals Hardness- use Moh’s hardness scale p 95 of textbook

Color Not good to use. Several minerals come in different colors.

Streak - color of the mineral’s powder found when the mineral is rubbed on a piece of tile

Luster - how a mineral reflects light: glassy, pearly, metallic, and earthy

Cleavage & Fracture Cleavage: split apart easily along flat surfaces. Fracture: irregular surface where it breaks

Cleavage

Fracture

Density Density = mass/volume Use a balance to find mass in grams Use a graduated cylinder to find volume in milliliters

Other Properties: Chemical reaction: fizzes with vinegar (Calcite) Transparent – can see through it Opaque – pearly, cloudy Magnetic * High Mass