Minerals

What is the difference in picture A and B? (Other than the obvious)

A B

What is a mineral?• Formed by natural processes such as

cooling magma and evaporating saltwater

• Inorganic – not made by life processes. Not alive.

• Element or a compound with definite chemical composition (structure)

• Solid and crystalline (atoms in patterns that repeat over and over again)

S.N.I.F.E.

Solid-not liquid, gas, or plasma

Naturally Occurring-Not manmadeInorganic–Not alive, never was

Fixed Composition - Same recipe everywhere, every timeElement or Compound-Not a mixture

How are minerals classified?

Minerals are grouped based on crystal

systems. This means that they are classified according to their type

of repeated crystal patterns.

How are minerals identified? (How can you tell them

apart?)•Color•Hardness•Luster•Specific

Gravity

•Streak•Breakage•Unique

properties

Color

• The appearance of color of a mineral.

• Minerals can also change colors when they react with air or water.

• Color is NOT very reliable for identifying minerals because colors can vary greatly and are not consistent.

• Streak tests are much more reliable.

HardnessHardness is determined by how easily a mineral can

be scratched.

Mohs Scale of Hardness is used to measure the hardness of a mineral

Mohs Hardness ScaleMohs Scale Hardnes

sHardness of

Common ObjectsTalc (softest) 1 Fingernail 2.5

Gypsum 2 Piece of copper 2.5-3.0

Calcite 3 Iron nail 4.5

Fluorite 4 Glass 5.5

Apatite 5 Steel file 6.5

Feldspar 6 Streak plate 7.0

Quartz 7 Flint sandpaper

Topaz 8 Spinel (rock shops)

Corundum 9 Emery sandpaper

Diamond (hardest) 10 Carborundum sandpaper

LusterThe way a mineral

reflects light (dull or shiny).

Metallic or Nonmetallic

Density

• D=M/V -g/cm3

• Is a measure of how much matter is in a given object.

Specific Gravity

The Density of the mineral in comparison to the Density of an

equal volume of water (1g/cm3).

• -Ex: Gold’s density is 19g/cm3. What is its Specific Gravity?

• SG=19g/cm3 divided by 1g/cm3

• SG=19

StreakThe color of a mineral when it is in powdered

form.

Tested by streaking the mineral across another object (object must be

harder than the mineral)

Breakage

Clevage-breaks along smooth, flat surfaces

Fracture-breaks with an uneven, rough, or jagged

surface

Unique PropertiesMany minerals have unique

characteristics that can also be used to identify the

mineral. Example-natural magnet, double refraction, odor, taste, reaction to acids,

fluorescence, etc.

Uses of Minerals• Minerals are a component of everyday life

because they are a part of everyday objects• Jewerly (gems-rare minerals)• Diamonds are used in industrial abrasives

and cutting tools• Some minerals are used to produce specific

types of laser light• Quartz is used in electronics• Minerals that contain useful substances can

be mined (Ex. Bauxite-aluminum; Ilemenite and Rutile-titanium)