Rocks and Minerals Minerals (by def)

- naturally occurring - inorganic

- solid- definite chemical composition- a crystal structure

Rocks and Minerals1. Naturally Occurring

mineral: quartz pyriteNot mineral: cement, steel

Rocks and Minerals2. Inorganic

- does not come from anything living

Ex: coal, pearls Amber (not minerals)

Definite Chemical CompositionName of Mineral

Chemical Formula

Chemical Name

Elements and no of atoms

Halite NaCl Sodium Chloride

1 sodium1 chlorine

Quartz SiO2 Silicon Dioxide 1silicon2 oxygen

Pyrite FeS2 Iron Sulfide 1 Iron2 sulfur

Hematite Fe2O3 Iron Oxide 2 iron3 oxygen

Magnetite Fe3O4 Iron Oxide 3 iron4 oxygen

Calcite CaCO3 Calcium Carbonate

1 Calcium1 Carbon3 Oxygen

Graphite C Carbon 1 CarbonDiamond C Carbon 1 CarbonSulfur S Sulfur 1 sulfur

Rocks and Minerals4. Solids: Have definite size/volumeand a definite shapeEx: oil, lava, magma

Rocks and Minerals5 Crystal Shape:Atoms arranged in repeating

patterns.

Mineral Formation1. From Cooling

lava/Magma2. When water evaporates,

dissolved minerals remain behind

(precipitate out)

Identifying MineralsIdentified by Physical and

Chemical propertiesPhysical: Color, Streak,

Luster, Hardness, DensityChemical: reactivity, special

properties

Physical Properties1. Color: (vary due to

impurities)a. Some minerals have only one color

- olivine: green

- sulfur: yellow

b. Others have many colors

- quartz: clear, pink, purple, white, smoky

- hematite: black, grey red-brown, dark red

Physical Properties2. Streak: color of powder when

mineral is rubbed on a streak plate

- Streak never changesEx: Hematite: color variesDark red, reddish brown, greyStreak: always reddish brown

Physical Properties3. Luster: the way a mineral

shines or reflects light from its surface

2 typesMetallic: shines/reflects light like a

metal (quarter)Nonmetallic: pearly, glassy, dull,

waxy, brilliant

Mineral Hardness Number Name of

mineral

1 talc2 gypsum3 calcite4 fluorite5 apatite6 feldspar7 quartz8 topaz9 corundum10 diamond

4. A measure of how easily a mineral can

be scratched

1 softest mineral10 hardest mineral

A mineral with a hardness 4 can

scratch itself and anything below

Mineral Hardness/Common Objects

2.5 Fingernail3.5 Copper Penny4.5 Iron Nail5.5 Glass Plate6.5 Steel File7 Streak Plate

Mineral Properties5. Cleavage and Fracturea. Cleavage: when a mineral

splits along smooth flat surfaces.

Ex: Mica: one direction

Mineral PropertiesEx: Galena: three directions

Determined by internal structure of mineral bonds between the atoms

Mineral Properties: CleavageCleavage does not = Crystal ShapeCrystal way mineral growsCleavage way mineral breaks

Mineral PropertiesFracture: mineral breaks unevenly

curved or irregular pieces

rough/jagged surfaces

Density or Heft6. Density: How closely the

atoms are packed into a given space.

Different minerals of the same size have different densities and feel heavier or lighter

Chemical PropertiesCalcite: reacts with HCL. It forms

bubbles of carbon dioxide gas

CaCO3 + 2HCl -> CaCl2 + H2O + CO2

Special PropertiesLodestone, a form of the mineral

magnetite is naturally magnetic

Calcite, shows double refraction

Pitchblende: is radioactive

Uses of MineralsA. Ore: A mineral that containsMetals and nonmetals that can be

removed in usable amounts for a profit.1. Metals: elements shiny surfaces conduct heat and electricity

Metals1. Iron: hematite: Fe2O3

Magnetite: Fe3O4

2. Aluminum: bauxite: Al(OH)3

3. Copper: Chalcopyrite: CuFeS2

malachite:Cu2CO3(OH)2

Metals4. Silver: Argenite: AgS2

5. Gold: Gold: Au

6. Mercury: cinnabar : HgS

AlloyA mixture of two or more metals or a

mixture of metals and nonmetals1. Tin + Copper -> bronze2. Zinc + Copper -> brass3. Iron + chromium + limestone ->

steel4. Tin + lead -> pewter

NonmetalsElements dull surfaces, poor

conductors of heat, electricity1. Halite: Salt: NaCL2. Gypsum: drywall3. Sulfur: matches4. Talc: talcum powder5. Graphite: pencils

GemsMinerals with desirable qualities

hardness, color, luster, rare, durable

Precious stones: diamonds, rubies sapphires

Semiprecious: amethyst, garnet topaz

Gems not minerals: pearls