Elements and Compounds in their solid form make up…

What is a Mineral?

A MINERAL is a naturally occurring, inorganic, solid, with a

definite chemical composition, and a crystalline structure.

That means that…

•It can’t be organic in origin•It can’t be a liquid •You could write a chemical formula for it•It has to have a crystal structure

How many different minerals are there on Earth???

Answer:About 4,000

Only 30 of the 4,000 known minerals are common.

These 30 minerals are known as the rock-forming minerals

More than 90% of all of the minerals in the Earth’s Crust are

made up of compounds containing Silicon and Oxygen, the two most abundant elements

on Earth.

SilicatesSilicates

Rocks that have a high percentage Rocks that have a high percentage of Silicates are light in color, and of Silicates are light in color, and

are called are called FelsicFelsic rocks. rocks.

Granite

Rocks that have a low Rocks that have a low percentage of Silicates are dark percentage of Silicates are dark

in color, and are called in color, and are called MaficMafic rocks. rocks.

BasaltBasalt

How do Minerals Form???

1. Minerals form in cooling magma chambersIGNEOUSIGNEOUS

Different types of minerals Different types of minerals crystallize at different crystallize at different

temperaturestemperatures

Decreasing temperature

Bowen’s Reaction SeriesBowen’s Reaction Series

Olivine

MINERAL!

Pyroxene

MINERAL!

Peridotite- Mostly Olivine

ROCK!!!

Gabbro- Pyroxene and Olivine

ROCK!!!

MINERAL!

MINERAL!

MINERAL!

MINERAL!

Andesite- Hornblend and Biotite? and Plagioclase Feldspar

ROCK!!!

ROCK!!!

Potassium Feldspar

MINERAL!

Quartz

MINERAL!

Pink Granite

ROCK!!!

Mineral Fractionalization in a Magma Chamber

2. Metamorphic MineralsMetamorphic Minerals:Some minerals occur as the

result of Recrystallization and Reaction within existing rocks which produces new minerals

in response to changes in

and

How do Minerals Form???

3. Some types of minerals form as water containing dissolved minerals slowly evaporates.

Salt deposits

How do Minerals Form???

SEDIMENTARY

Minerals are identified and classified by visual inspection, and

by performing simple tests to determine their physical properties

Minerals are most often identified by inspecting their

Physical and Chemical properties.

Color is the most easily observed, but least reliable property of a mineral for identification.

This is because the color of many minerals varies with the kind of impurities in the mineral.

LusterLuster is the way in which a mineral reflects light.• Metallic• Nonmetallic

• shiny, glassy, dull, earthy, vitreous, brilliant, waxy, pearly

Streak is the color of the powder left on a streak plate when a mineral is rubbed on it.

Streak is much more reliable than color because, although the color of a mineral changes, its streak does not.

Cleavage is the tendency of a mineral to split in a particular direction.

“Sheety” Cleavage

Feldspars always cleave readily at or near right angles.

Fracture is the tendency of a mineral to break in directions other than along crystal faces or cleavage surfaces.

Fracture

Conchoidal Fibrous Irregular

Obsidian Asbestos Quartz

Conchoidal or shell-like fracture

Fibrous facture

The orderly arrangement of ions, molecules, or atoms, in any

mineral determines the shape of its crystals.

Hardness is the resistance of a mineral to Hardness is the resistance of a mineral to being scratched.being scratched.

(Harness and strength are NOT the same (Harness and strength are NOT the same thing! Diamonds are hard, but not strong!)thing! Diamonds are hard, but not strong!)

Moh’s Mneumonic

Three Groovy Cats Found A Ferret Quietly Toasting Cheese Dinners.

Specific Gravity• The ratio of the density of

a min’l to the density of pure water: “heft test”

Pure water: 1.0 Pyrite: 5.0 Most metals > non-metals

Special Properties• Smell: Sulfur• Light refraction: Ulexite• Magnetic: Magnetite• Taste: Halite• Chem. rxn w/ HCl:

Calcite

More Special Properties

• Asterism:

• Chatoyancy: silky look