MineralsMinerals

Background InformationBackground Information Element: a substance made up of only Element: a substance made up of only

one kind of atomone kind of atomExample: Gold (Au), Aluminum (Al)Example: Gold (Au), Aluminum (Al)

As of 2011, there are 118 As of 2011, there are 118 elements, elements, 90 are naturally occurring.90 are naturally occurring.

Compound:Compound: a mixture of two or more a mixture of two or more elementselementsExample: Salt (NaCl)Example: Salt (NaCl)Sodium and ChlorineSodium and Chlorine

What is a Mineral?What is a Mineral?

1.1. Naturally occuringNaturally occuring2.2. Inorganic—Not LivingInorganic—Not Living3.3. SolidSolid4.4. Crystal StructureCrystal Structure5.5. Definite Chemical CompositionDefinite Chemical Composition

Minerals can form two Minerals can form two waysways

1. Magma and Lava1. Magma and Lava• Minerals form as hot magma cools inside Minerals form as hot magma cools inside

the crust, or as lava hardens on the the crust, or as lava hardens on the surface.surface.

• When these liquids cool to a solid state, When these liquids cool to a solid state, they form crystals.they form crystals.

2.2. SolutionsSolutions Solution is a mixture in which one Solution is a mixture in which one

substance is dissolved in another.substance is dissolved in another. When elements and compounds that When elements and compounds that

are dissolved in water leave a solution, are dissolved in water leave a solution, crystallization occurs.crystallization occurs.

Some minerals form Some minerals form when solutions when solutions evaporate.evaporate.

Example: Death ValleyExample: Death Valley

Identifying a MineralIdentifying a Mineral

• Each mineral has characteristic Each mineral has characteristic properties that can be used to identify it.properties that can be used to identify it.

ColorColor Color of a mineral is an easily observed Color of a mineral is an easily observed

physical property.physical property. Light or Dark?Light or Dark?

HaliteHalite hematitehematite

StreakStreak The mineral is rubbed against a piece of The mineral is rubbed against a piece of

unglazed porcelain tile.unglazed porcelain tile. Sometimes the streak color and the Sometimes the streak color and the

mineral color are different.mineral color are different. Ex: gold-gold pyrite-greenish black Ex: gold-gold pyrite-greenish black

LusterLuster Luster is how a mineral reflects light.Luster is how a mineral reflects light.

MetallicMetallic Nonmetallic—includes glassy, earthy, waxy Nonmetallic—includes glassy, earthy, waxy

and pearly.and pearly.GalenaGalena QuartzQuartz

DensityDensity Each mineral has a characteristic Each mineral has a characteristic

density.density. Density = mass/volumeDensity = mass/volume

HardnessHardness11 SoftestSoftest Ex. TalcEx. Talc FingernailFingernail22 Ex. GypsumEx. Gypsum fingernailfingernail33 Ex. CalciteEx. Calcite PennyPenny44 Ex. FlouriteEx. Flourite Steel knifeSteel knife55 Ex. Apatite Ex. Apatite Steel knife can Steel knife can

scratch itscratch it66 Ex. Feldspar Ex. Feldspar

It can scratch glassIt can scratch glass

77 Ex. QuartzEx. Quartz Steel & hard glassSteel & hard glass88 Ex. TopazEx. Topaz Can scratch quartzCan scratch quartz99 Ex. Ex.

CorundumCorundumCan scratch topazCan scratch topaz

1010 HardestHardest Ex. DiamondEx. Diamond Will scratch all Will scratch all other substancesother substances

CleavageCleavage A mineral that splits easily along flat A mineral that splits easily along flat

surfaces.surfaces.

FractureFracture Fracture is when a mineral breaks in an Fracture is when a mineral breaks in an

irregular way.irregular way.

Crystal StructureCrystal Structure Each mineral grows atom by atom to Each mineral grows atom by atom to

form a particular crystal structureform a particular crystal structure Two main typesTwo main types

Cubic--HaliteCubic--Halite Hexagonal--QuartzHexagonal--Quartz