Chapter 2 MineralsChapter 2 MineralsRemember >>>> The Earth is made Remember >>>> The Earth is made

of of mattermatter

Matter- anything that has mass & anything that has mass & takes up spacetakes up space

Most Most solidsolid matter on Earth is either: matter on Earth is either:

• a a mineralmineral

• a a rock rock (but a rock is just a (but a rock is just a mixturemixture of minerals)of minerals)

What is a Mineral ?What is a Mineral ?

- Natural (not man-made)- Natural (not man-made)- - InorganicInorganic (never living) (never living)

- - SolidSolid

- Has an orderly structure of - Has an orderly structure of atomsatoms

- Has a definite - Has a definite chemical compositionchemical composition

Minerals:Minerals:

Locating and Mining Minerals

• Minerals can be found in:• Rocks

• Sand

• Soil

• Seashells

• Below Earth’s surface

• Minerals are dug or mined out of the earth

• People mine for minerals on every continent except for Antarctica

• Minerals can be strip-mined or dug far below the earth’s surface

• Often minerals need to be separated from rock.

• Geologists can melt the minerals or use chemicals to break apart the rock

So how do we identify minerals?

How do I identify different How do I identify different minerals ?minerals ?

• COLOR• Color is not always good to use• All of these are quartz

Use 7 other properties to Use 7 other properties to identify minerals:identify minerals:

1.1. StreakStreak = color of mineral in = color of mineral in powderedpowdered form form

- rub - rub mineralmineral across a across a streak streak plateplate to see the to see the color color

7 Mineral Properties Cont…2. 2. LusterLuster = how = how lightlight reflects off reflects off surface surface

of mineralof mineral

A. A. MetallicMetallic = looks like shiny = looks like shiny metalmetal

B. Vitreous (B. Vitreous (glassyglassy) = shines like ) = shines like glassglass

C. Dull C. Dull

D. D. WaxyWaxy

7 Mineral Properties Cont…7 Mineral Properties Cont…

3. 3. Crystal FormCrystal Form = outward = outward shapeshape of mineralof mineral

- as mineral - as mineral growsgrows in size it will in size it will alwaysalways keep the same keep the same crystal crystal formform

A. A. CubicCubicB. Sheet-LikeB. Sheet-LikeC. Rhombohedral C. Rhombohedral D. D. MassiveMassive = no crystal form = no crystal form

7 Mineral Properties Cont…

4. 4. HardnessHardness = resistance of mineral to being = resistance of mineral to being scratchedscratched- rub 2 minerals together, the harder mineral will scratch - rub 2 minerals together, the harder mineral will scratch the softer mineralthe softer mineral- use the - use the Moh’s Hardness ScaleMoh’s Hardness Scale to find hardness range to find hardness range for minerals:for minerals:

1 - Talc1 - TalcSOFTESTSOFTEST

fingernail 2.5fingernail 2.5 2 - Gypsum2 - Gypsum3 - Calcite3 - Calcite

steel nail 4.5steel nail 4.5 4 - Fluorite4 - Fluoritemanufactured glass 5.5manufactured glass 5.5 5 - Apatite5 - Apatite

6 - Orthoclase6 - Orthoclase7 - Quartz7 - Quartz8 - Topaz8 - Topaz9 - Corundum9 - Corundum10 - Diamond 10 - Diamond HARDESTHARDEST

7 Mineral Properties Cont…7 Mineral Properties Cont…

5. 5. CleavageCleavage = tendency of a mineral to break along = tendency of a mineral to break along smooth, even surfaces (always in the same smooth, even surfaces (always in the same direction/directions)direction/directions)

A. A. 1 Direction1 Direction = always breaks into sheets = always breaks into sheets EX: Muscovite & BiotiteEX: Muscovite & Biotite

B. B. 2 Directions @ 90°2 Directions @ 90° = mineral always breaks into = mineral always breaks into squaressquares

EX: GalenaEX: GalenaC. C. 3 Directions @ 90°3 Directions @ 90° = mineral always breaks into = mineral always breaks into

cubes cubes EX: HaliteEX: Halite

Some minerals do not display cleavage, this property Some minerals do not display cleavage, this property is called is called Fracture Fracture EX: QuartzEX: Quartz

7 Mineral Properties Cont…7 Mineral Properties Cont…

6. Density 6. Density ((Specific GravitySpecific Gravity) ) = how = how heavyheavy a mineral feels a mineral feels

EX: EX: GalenaGalena is very is very heavyheavy for for its its sizesize

EX: EX: TalcTalc is very is very light light for its for its sizesize

7.7. OtherOther Properties Properties

A.A. Smell Smell = some mineral have a distinct smell = some mineral have a distinct smell

EX: EX: SulfurSulfur smells like smells like rotten eggsrotten eggs

B. Feel = some minerals feel B. Feel = some minerals feel greasygreasy

EX: GraphiteEX: Graphite

C. C. MagneticMagnetic = some minerals behave as = some minerals behave as magnetsmagnets

EX: MagnetiteEX: Magnetite

D. D. TasteTaste = = salty taste salty taste of Halite of Halite

CAUTION: DO NOT TASTE ANY MINERALCAUTION: DO NOT TASTE ANY MINERAL

E. E. Reacts to AcidReacts to Acid = some minerals fix when a = some minerals fix when a weak acid (HCL) is dropped on themweak acid (HCL) is dropped on them

EX: EX: CalciteCalcite

Do I use minerals Do I use minerals ??

YESYES1.1. SaltSalt (halite) (halite)2.2. pencil lead (pencil lead (graphitegraphite))3.3. make-upmake-up (talc) (talc)4.4. window glass (window glass (quartzquartz))

How do minerals form?How do minerals form?

4 Main Ways:4 Main Ways:

1. 1. CrystalsCrystals form out of form out of magmamagma

2. Precipitate (2. Precipitate (solid formssolid forms) out of water) out of water

3. Change in 3. Change in pressurepressure and temperature and temperature

4. From 4. From hothot waterwater = (causes chemical = (causes chemical reactions to form new minerals)reactions to form new minerals)

6 Major Mineral Groups:6 Major Mineral Groups:

1. Silicates = minerals that contain elements silica, oxygen and other minor elements

EX: Quartz, Olivine, Muscovite, Biotite, Feldspar- form from cooled magma

2. Carbonates = minerals that contain oxygen, carbon, and other minor elements

EX: Calcite- form in shallow oceans

3. Oxides = minerals that contain mainly oxygen and minor elements

EX: Hematite- form in variety of environments

4. Sulfates & Sulfides = minerals that contain sulfur and other minor elements

EX: Gypsum, Galena, Pyrite- forms in hot water solutions

5. Halides = minerals that contain fluorine, chlorine, and other minor elements

EX: Halite- forms from evaporation/precipitation

6 Major Mineral 6 Major Mineral Groups:Groups:

6. Native Elements = pure single forms of minerals

EX: Gold, Silver, Copper, Sulfur, Diamond, Graphite- forms in hot water solutions

What is a gemstone?What is a gemstone?• Any mineral that can Any mineral that can

be cut, polished, and be cut, polished, and sold for a profitsold for a profit

EX: EX: - DiamondDiamond- RubyRuby (mineral (mineral

Corundum) = RedCorundum) = Red- EmeraldEmerald (mineral Beryl) (mineral Beryl)

= Green= Green- AmethystAmethyst (mineral (mineral

Quartz) = PurpleQuartz) = Purple- SapphireSapphire (mineral (mineral

corundum with corundum with impurities of titanium) = impurities of titanium) = BlueBlue