Characteristics & Properties

What is a Mineral?

Must meet 5 characteristics

One of these is an mineral and the other is not…

Naturally Occurring

The growing process must occur in the natural world

Heating/cooling processes in magma

Inorganic

Cannot form from materials that were once part of a living thing

Coal

Obsidian

Solid

Definite volume & shape

The particles must be pressed tightly together

Crystal Structure

The particles must line up in a pattern= that forms a crystal

Flat sides are faces

Faces meet at edges and corners

http://nanocrystallography.net/images/swpb3.pdf

Definite Chemical Compound

This means that a mineral always contains certain elements in definite proportions

Almost all minerals are compounds

Their properties will be different from the

Some elements can be a mineral

NO Naturally Occurring

Illegal Inorganic

Science Solid

'Cause Crystal

Science Structure

Can -

Definitely Definite

Cause Chemical

Catastrophes Compound

Identifying Minerals

Gold PyriteChalcopyrite

ColorPhysical property

Can only be used to ID a few minerals

Many minerals have the same color

Streak

Color of the powder form of the mineral

Not always the same as the physical color of the mineral

Luster of Minerals

Metallic Glassy Waxy, Greasy, Pearly

Submetallic/Dull Silky Earthy

Luster how light reflects from the faces of the crystal

Heft/Density

Mass in a given space (mass/volume)

Heft- picking up and feeling – has to be done with minerals of similar sizes

Find density using displacement

Hardness

Moh’s Hardness Scale

A mineral can scratch any mineral softer than itself

Crystal Structure

Geologists classify the crystal structures into 6 groups

Structure is obvious when grown with plenty of space

Crystals grown in tight spaces are often incomplete

Some only visible under microscope

Opal is the exception to the rule- no crystal structure

Crystal StructuresCubic Hexagonal Tetragonal

Orthorhombic Monoclinic Triclinic

Cleavage & FractureCleavage:

splits easily along flat surfaces

Depends on arrangement of atoms

Fracture

How a mineral looks when it breaks apart in a irregular way

Special Properties

Fluorescence

Electrical Properties

Optical Properties

Reactivity

Magnetism

Calcite

AragoniteMagnetite