rocks and minerals

what is a mineral

naturally occurring

inorganic- no carbon bound to hydrogen

crystal structure

solid (glacier v liquid water)

specific chemical composition

what are polymorphs

when twi minerals have the same elements in the same ratio but the atoms are arranged differently

WHAT IS CRYSTAL FORM

a minerals external shape- well formed crystals are rare to find in nature

WHAT IS HARDNESS

resistance to scrationg

strength of a minerals chemical bond

mohs scale of hardness

WHAT IS CLEAVAGE

a minerals tendency to break along distinct planes of weakness

WHAT IS FRACTURE

when minerals do not exhibit cleavage and they fracture

WHAT IS LUSTER

the ability of a mineral to reflect light

what are different types of luster

metallic

earthy

waxy

what is a minerals specific gravity

ratio weight to mineral to weight of water

what is the best way to identify a mineral

SPECIFIC GRAVITY

what is a streak

color of a mineral in powdered form

not always the same color!

what is the streak plate made of

unglazed porcelain

what are the types of minerals

silicates

non silicates

why are there only silicates and non silicates

Si and O are 75% of earths crust

only 8 elements make up 98% of earths mass

what are silicates

minerals that contain si and o bonded together

-ferromagnesian

-nonferromagnesian

what are ferromagnesian silicates

iron and magnesium contained

dark, dense, and glassy

OCEANIC CRUST

what are nonferromagnesian silicates

lighter and less dense

CONTINENTAL CRUST

what are nonsilicates

8% of earths crust

used in cements

used in manufacturing (medical, airplane parts)

native elements- copper, carbon, sulfur

how do minerals form

crystallization!- growth of a solid whose atoms come together in a specific structure

what are types of crystallization

cooling magma

hydrothermal solutions

precipitation

pressure and temp

cooling magma crystallization

temp increased 30 degrees c every km below grounf

liquid magma rises and cools- as it cools, minerals form

-diff min at diff temps

-quick cooling above ground- small crystals

-slow cooling blow ground-LARGE CRYSTALS

hydrothermal solution crystallization

mix of very hot water and dissolved substances

dissolves minerals and other substances crystalize out if solution when saturated

-rock candy experiment!

evaporation crystallization

surface water contains many dissolved substances

evaporation of water leaves particles behind to form minerals

-ex halite; rock salt

pressure and temp changes crystallization

new minerals can form within rocks based on these two factors

-metamorposis

-ex diamond v graphite

where are minerals mined from

the earths crust

how many tons of minerals are needed to be mined each year

several billion tons

what is ore

mineral deposits that are large enough and pure enough to be mined for profit

examples of surface mines

open pit, strip mining, and quarries

what are the downsides to surface mining

changes the earths surface significantly

can generate significant erosion

what is a rock

solid, cohesive mix of mineral crystals

surface rock is created by soil

what is soil

mix of weathered rock, air, water, and organic matter

what are the three kinds of rock

igneous

sedimentary

metamorphic

what are igneous rocks

CRYSTALLIZATION AND SOLIDIFICATION OF MAGMA THAT IS COOLING

-tightly interlocking crystals

-granite!

what are sedimentary rocks

accumulation of weathered materials

rocks on the surface weather

5% of earths crust

forms layers called strata

can contain fossils

biological processes can create

which direction does erosion move sediment

downhill!!! toward body of water (usually)

what is lithification

sediment is compacted by weight of overlying layers

held together by natural cement

-sedimentary rock

how much of continental crust is sedimentary rock

75%! the most encountered rock

what is limestone

sedimentary rock

-marine animals extract CaCO3 from ocean water

-she;;s sink to ocean bottom

-buried, compacted, cemented

what is coal

combustible sedimentary rock

-10 trillion tons stored in the crust

-derived from ancient land plants (300 mya)

-steamy swamps

how much energy do coal plants produce

~16% us

~38% global

verrryyyyyy bad for enviro

what are metamorphic rocks

rocks that change form deep in the earths interior to become more stable under new conditions

few km below surface all the way to crust-mantle boundary

many are foliated

what does foliated mean

minerals are aligned in a specific direction forming parallel layers

-distinct bonding of light and dark minerals

nonfoliated- no layers; marble!