crystallography earth materials assessment

20 minerals and crystals

calcite hardness, cleavage, and rxn w/ acid

hardness: 3

cleavage: 3 planes

rxn w/ acid: YES

calcite crystallography, chemical composition, and mineral group

crystallography: rhombohedron

composition: CaCl3

mineral group: carbonate

calcite color

translucent/ white/ cloudy

corundum hardness, streak, and crystallography

hardness: 9

streak color: brown

crystallography: hexagonal prism

corundum chemical composition, and mineral group

chemical composition: Al2O3

mineral group: oxide

where is calcite found?

limestone

what is corundum also known as?

ruby and sapphire

what color is RAW corundum?

rusty brown, NOT metallic though

potassium (K) Feldspars other name

orthoclase feldspar

potassium (K) feldspars hardness and cleavage

hardness: 6

cleavage: 2 planes at 90 degrees

potassium feldspars crystallography, and mineral group

crystallography: Triclinic

mineral group: silicate

potassium feldspar color

salmon/ pink

Sodium Na) feldspars other name

plagioclase feldspar

sodium feldspars color

off white/ white-ish

sodium feldspar hardness, and cleavage

hardness: 6

cleavage: 2 planes of cleavage at 90 degrees

sodium feldspars crystallography, and mineral group?

crystallography: triclinic

mineral group: silicate

Are the feldspars (K and Na) sedimentary, igneous, or metamorphic?

igneous

Fluorite color

in the case we studied, it is purple/ blue

fluorite hardness and cleavage

hardness: 4

planes of cleavage: 4

fluorite crystallography, chemical composition and mineral group

crystallography: octahedron

composition: CaF2

mineral group: Halide

Galena hardness, streak, and cleavage

hardness: 2.5

streak color: gray

Cleavage: 3 planes at 90 degrees

galena chemical composition, crystallography, and mineral group

crystallography: isometric cube

composition: PbS

mineral group: sulfide

Galena color

metallic gray

How heavy is galena and why?

has a s.g of 7.5 (very heavy; heaviest in kit) because of its lead composition

uses for galena

has many industrial uses

Garnet hardness and crystallography

hardness: 7

crystallography: dodecahedron

garnet mineral group

mineral group: silicate

garnet color

red/ brown

is graphite metallic or non metallic?

it is metallic

Graphite hardness and streak

hardness: less than 2.5 (very soft)

Streak: grey

graphite crystallography, chemical composition, and mineral group

Crystallography: Hexagonal flakes

chemical composition: C

mineral group: native element (bc C)

besides graphite, what other mineral has the chemical composition of C?

Diamond

Besides graphite, what is one of the softest minerals?

gypsum

what does graphite look like?

gypsum hardness and crystallography

hardness: 2 (one of the softest minerals)

crystallography: monoclinic

gypsum chemical composition and mineral group

chemical composition: CaS

mineral group: sulfate

what does gypsum look like?

clear-ish with tiny fibers

Halite uses

rock salt

Halite hardness and planes of cleavage

hardness: 2.5

cleavage: 3

Halite crystallography, mineral group, and chemical composition

crystallography: cubic

Mineral group: halide

composition: NaCl

Hematite luster, hardness, and streak

luster: metallic

hardness: varies

streak: red/ brown

Hematite crystallography, composition, and mineral group

Crystallography: rhombohedral

composition: FeO3

mineral group: oxide

hematite S.G

very heavy due to its Fe content

Hornblende hardness, cleavage, and streak

Hardness: less than 5.5

cleavage: 2 planes at 90 degrees

streak: gray/ white

hornblende crystallography and mineral group

crystallography: prism

mineral group: silicate

what does hornblende look like?

black and non metallic

magnetite luster, hardness, and streak

luster: metallic

Hardness: less than 5.5

streak: black

magnetite crystallography, chemical composition, and mineral group:

crystallography: octahedron

composition: FeO4

Mineral group: oxide

what is another name for hornblende?

Amphibole

Biotite/ muscovite hardness and cleavage

hardness: around 2.5

cleavage: 1 plane

Biotite/ muscovite crystallography and mineral group

crystallography: monoclinic

mineral group: silicate

where is olivine located on earth?

very deep in the earths crust (ultra mafic)

olivine hardness and crystallography

hardness: less than 5.5

crystallography: varies

olivine mineral group

mineral group: silicate

pyrite luster, hardness, cleavage, and streak

luster: metallic

hardness: greater than 5.5

cleavage: 3 planes

streak: gray

pyrite crystallography, chemical composition, and mineral group:

crystallography: cubic pyritohedron

composition: FeS2

mineral group: sulfide

quartz hardness and fracture

hardness: 7

fracture: conchoidal fracture

quartz crystallography, composition, and mineral group

crystallography: hexagonal prism

composition: SiO2

Mineral group: silicate

sulfur hardness and crystallography

hardness: more than 2.5

crystallography: orthorhombic

sulfur composition and mineral group

composition: S

mineral group: native element

Talc hardness and crystallography

hardness: 1

crystallography : monoclinic

talc mineral group

mineral group: silicate

what is talc in?

baby powder

isometric cube:

six square faces

ex) galena and halite

octahedron

eight triangular faces

ex) magnetite and flourite

pyritohedron

12 pentagonal faces

ex) pyrite

dodecahedron

12 diamond shaped faces

ex) garnet

hexagonal prism

6 rectangular faces parallel to c-axsis

ex) quartz

rhombohedron

6 parallelogram faces inclined to c-axsis

ex) hematite and calcite

monoclinic

four rectangular faces

ex) gypsum, Biotite/ muscovite, and talc