Minerals Formation, Characteristics and Identifying Properties

What is a Mineral? A Naturally occurring InorganicHomogenousCrystalline Single solid substance

Why study minerals? Minerals are important in our everyday lives ( go on a mineral scavenger hunt...)

Asbestos All pictures are from:

Calcite note shape of crystal

Garnet NY State Mineral

Diamond The hardest mineral

What is a crystal? A solid with a regular geometric shape resulting from the internal arrangement of atoms which make it up 6 basic shapes

What do all these minerals have in common? List in your notes: List in your notes:

Crystal Shapes: (see handout) Crystal shape is due to the molecular arrangement of atoms Shapes include:

How Do Minerals Form? Cooling of magma (crystallization) Heat and pressure (recrystallization) Evaporates or precipitates from seawater

Cooling from magma

What Determines the Size of the Crystal/Mineral? Cooling time coarse or large crystals have a long cooling time fine or small crystals have a short cooling time

Identifying Minerals: We use observable and testable characterics to identify minerals

Easily Observable Characteristics: Color Luster(way the mineral reflects light) Crystal Shape

Testable Characteristics: Hardness (Moh’s Scale) Streak (color of mineral in powdered form) Acid Test Cleavage vs. Fracture Specific Gravity Fluorescence

Color This is the least reliable property to use to identify a mineral

Luster Metallic or Non-metallic

Streak Rub mineral along porcelain streak plate

Moh’s Scale

Cleavage vs. Fracture This is the way the mineral breaks -if it breaks along a plane then it cleaves, if it shatters then it fractures

Use these tests to help you identify minerals in lab...

Other mineral properties- Flourescence- These minerals glow under special light Double refraction-bends light so words appear twice (calcite) Magnetism Are magnetic Specific gravity- density of mineral compared to water

Mineral Families Native Elements: consist of a single element Halides: consist of a metal plus a halogen (noble gas-Cl, F, Ne, He) Carbonates: consist of a metal and carbonate group (CO 3 ) Sulfides: consist of metal and sulfur Sulfates: consist of a metal and sulfate group (SO 4 ) Oxides: consist of metal and oxygen Silicates: consist of silicon and oxygen (SiO 4 or SiO 2 )

Other facts: Rare minerals of great beauty and value are classified as gems (ex: diamonds, rubies) Minerals that have a commercial value and use and can be extracted from the earth are ores. These are usually metals. (ex: lead, iron) We are studying minerals or mineralology