Minerals!

Question 1

Quartz

Answer 1

SiO2
hardness: 7
streak: none
Cleavage: conchoidal
Luster: vitreous (glassy)
colorless, white, blocky

Question 2

Orthoclase

Answer 2

(Feldspar)
Potassium rich
Hardness: 6
Fracture: 90 degree in 2 directions
Streak: White
Color: flesh pink/ off white

Question 3

Plagioclase

Answer 3

(Feldspar)
Sodium to calcium
Hardness: 6
Streak: Colorless
colorless/white

Question 4

Muscovite

Answer 4

Potassium
type of mica
cleavage: good in 1 direction (flexible)
Hardness: 2-2.5
color-less to light yellow

Question 5

Biotite

Answer 5

Magnesium and Potassium
cleavage: good in 1 direction (flexible)
super flaky, thin, black/brown

Question 6

Calcite

Answer 6

CaCO3 (calcium)
Hardness: 3
Effervescence: strong reaction
Fracture: forms rhombohedra
White to colorless
kinda looks like quartz, but a lot softer.

Question 7

Dolomite

Answer 7

Calcium and Magnesium
Effervescence: mild reaction
Pink, flesh, white, kinda ashy

Question 8

Apatite

Answer 8

Phosphorous
Luster: vitreous (glassy)
green!

Question 9

Olivine

Answer 9

Magnesium
Fracture: Conchoidal
sandy olive

Question 10

Hornblende

Answer 10

Magnesium and Calcium
Cleavage: Prismatic
Black or dark green

Question 11

Serpentine

Answer 11

Magnesium
Luster: greasy
Variegated greens

Question 12

Hematite

Answer 12

Iron
Streak: dusky red
Black to reddish brown color

Question 13

Limonite

Answer 13

Iron
Streak: yellow-brown streak
dark brown to black color

Question 14

Pyrite

Answer 14

FeS2
Hardness: 6-6.5
Streak: green to brownish black
Luster: metallic
Brass yellow color
Fool’s Gold!!

Question 15

Gypsum

Answer 15

CaSO4
Hardness: 2 (so soft)
Luster: shiny, pearly
colorless white or grey

Question 16

Luster

Answer 16

appearance of a mineral in reflected light
Metallic: appears as a shiny metal (pyrite(fool’s gold))
Non-metallic:
vitreous- glassy (quartz)
Pearly- iridescent (gypsum)
Greasy- oily (serpentine)

Question 17

Hardness

Answer 17

resistance to being scratched
(harder than a pice of material if it can scratch it without being scratched)
Fingernail 2 (gypsum)
Copper penny 3 (calcite)
Steel file 5
glass 5.5
knife 6.5 (feldspars-6)
porcelain 7 (quartz)

Question 18

Streak

Answer 18

When a mineral is scratched against an unglazed porcelain plate it leaves a streak
Hematite- burgundy
limonite- yellow brown
orthoclase- white
plagioclase- clear
minerals greater than 7 will not leave a streak (quartz)

Question 19

Color

Answer 19

Good for identifying the key elements in dark (Fe) vs light minerals (Ca)
Some minerals have distinct colors:
Olivine- sandy olive
Apatite- green
Pyrite- metallic gold

Question 20

Cleavage

Answer 20

A mineral with good cleavage will break along smooth surfaces
Micas- thin sheets (muscovite, biotite)
Feldspars- in two directions into rhombohedra (orthoclase, plagioclase)

Question 21

Fracture

Answer 21

If there is no good cleavage, there will be a fracture when chipped or broken:
conchoidal- smooth, curved surfaces (quartz, obsidian)
fibrous- breaks into fibers…
uneven- rough surface with irregularities

Question 22

Specific Gravity

Answer 22

ratio of its mass to that of equal volume of water (higher specific gravity means heavier mineral)

Question 23

Effervescence

Answer 23

Carbonate minerals release bubbles of CO2 when reacting with HCl. It’s. diagnostic for calcite (composed of CaCO3)

Question 24

Mineral

Answer 24

naturally occurring substance with distinct characteristics and chemical/ physical composition