Geology Exam minerals

·         Hardness = 1

·         Pearly luster

Talc

·         Hardness = 2

·         You will see a specimen of selenite gypsum

o   Colorless or “cloudy” with lines

Gypsum

·         Hardness = 3

·         PINK DOT – Will fizz/react with dilute hydrochloric acid

·         Chemical formula = CaCO₃

·         Cleavage = 3-directions

·         You will see a huge calcite specimen – but it has a PINK DOT

·         You will see an Iceland spar

o   Double refraction property

Calcite

·         Hardness = 4

·         You will see an octahedral (8-sided) fluorite (looks like a diamond)

o   This specimen is showing 4-direction cleavage

·         You will see cubic fluorite crystals

Fluorite

·         Hardness = 6

·         All feldspar cleavage = 2-directions at 90 degrees

·         Vitreous luster

§  Green like the amazon!

§  Special property is exsolution lamellae (linear blobs)

Feldspar Amazonite (microcline)

·         Hardness = 6

·         All feldspar cleavage = 2-directions at 90 degrees

·         Vitreous luster

§  Salmon/peach color  

Exsolution lamellae (linear blobs)

Feldspar Orthoclase

PLAGIOCLASE FELDSPAR GROUP

Hardness = 6

·         All feldspar cleavage = 2-directions at 90 degrees

·         Vitreous luster

o   1) Albite

§  White and grey

Striations (linear features/lines down the side)

PLAGIOCLASE FELDSPAR Albite

·         Hardness = 7

Chemical formula = SiO₂

·         Hexagonal crystal shape

·         Conchoidal fracture

·         You will see milky quartz

You will see a quartz geode

o   Sparkly inside

·         You will see a colorless/clear hexagonal quartz crystal   

·    You will see amethyst Purple color

Quartz

·         Hardness = 8

·         1-direction cleavage

Topaz

·         Hardness = 9

·         Hexagonal crystal shape

Corundum

·        

“Fool’s gold”

·         Cubic crystal shape

·         Use = Sulfur

Pyrite

·         3-direction cleavage

Use = Lead

Galena

·         Very magnetic

·        Octahedral crystal shape

Magnetite

Mineral streak (powder) smells like rotten eggs

Sphalerite

Gray mineral but it has a RED-BROWN streak

Hematite

·         Metallic luster

Native copper

·         Rainbow metallic mineral – sort of looks like an oil slick

·         Irregular fracture

·         Use = Copper

Submetallic luster

Bornite

·         Dark brown and “flaky”

·        1-direction cleavage

Biotite mica

·         Silvery/colorless and “flaky”

Muscovite mica

·        

YELLOW DOT – Will fizz/react with dilute hydrochloric acid when POWDERED

Dolomite crystals

·         Has striations, a distinctive property

Tourmaline

·         Dull (earthy) luster

·         Looks like clay

kaolinite

·         Black mineral

·         No striations

·         Vitreous luster

·         Splintery appearance

·        Common as elongate (long) crystals

Hornblende (amphibole)

·         Black mineral (might have some green)

·         Short blocky crystals

Augite (pyroxene)

·         Red-brown

·         12-sided

·         Kind of looks like a D&D die

Garnet

·         Chemical formula = KCl

·         Use = Salt substitute

Sylvite

·         Television” mineral – letters/writing will appear to be at the top surface of the mineral, like a TV screen

·         Fiber optical property

Ulexite