Quiz 11/17/2016 physical properties

Question 1

corundum

Answer 1

color: white/grey, sapphire blue, ruby/red
streak: white
hardness: 9
fracture: uneven, brittle, conchoidal
luster: vitreous
system: hexagonal

Question 2

hematite

Answer 2

color: steel grey (coarse); dull to bright red/brown (fine grained)
streak: rich red brown
hardness: 5-6
fracture: parting due to twinning, uneven, brittle
luster: crystalline samples = metallic; fine grained = dull/earthy
system: hexagonal

Question 3

ilmenite

Answer 3

color: black
streak: black
hardness: 5-6
fracture: irregular, brittle
luster: metallic
system: hexagonal

Question 4

magnetite

Answer 4

color: black, some orange from iron oxidizing
streak: black
hardness: 5.5-6
fracture: none/uneven, brittle, some parting, strong magnetism
luster: submetallic
system: isometric

Question 5

pyrolusite

Answer 5

color: dark grey/black
streak: blue/black to black
hardness: 6-6.5
fracture: splintery/uneven; branching
luster: metallic
system: tetragonal
* looks like plant

Question 6

spinel

Answer 6

color: green, green/blue, blue, red; becomes darker with Fe content (black)
streak: white
hardness: 7.5-8
fracture: parting, conchoidal, uneven, brittle
luster: vitreous
system: isometric

Question 7

graphite

Answer 7

color: silver-grey to black
streak: black
hardness: 1-2
fracture: conchoidal
luster: metallic
system: hexagonal

Question 8

copper

Answer 8

color: light rose to copper red; blue/green when tarnished
streak: brown-red
hardness: 2.5-3
fracture: spread; no definite shape
luster: metallic
system: isometric

Question 9

molybdenite

Answer 9

color: lead grey in thin flakes *looks like graphite; can be pale yellow or red-brown
streak: blue/grey
hardness: 1-1.5
fracture: perfect on {001}
luster: metallic
system: hexagonal

Question 10

realgar/orpiment

Answer 10

color: red, yellow to orange
streak: red/yellow/orange
hardness: 1.5-2
fracture: irregular
luster: resinous to greasy
system: monoclinic

Question 11

sphalerite

Answer 11

color: pale yellow, light brown to black; red or green; darker with Fe content
streak: white to light/med brown
hardness: 3.5-4
fracture: perfect {011} cleavage, conchoidal, brittle
luster: resinous, submetallic
system: isometric

Question 12

galena

Answer 12

color: lead grey
streak: lead grey
hardness: 2.5
fracture: perfect cubic cleavage
luster: metallic
system: isometric

Question 13

chalcopyrite

Answer 13

color: brass yellow
streak: greenish/black
hardness: 3.5-4
fracture: uneven
luster: metallic
system: tetragonal

Question 14

pyrrhotite

Answer 14

color: bronze yellow, reddish/brown cast
streak: dark grayish black
hardness: 3.5-4.5
fracture: none/uneven/ very brittle
luster: metallic
system: monoclinic

Question 15

pyrite

Answer 15

color: pale brass yellow
streak: greenish black to brown black
hardness: 6-6.5
fracture: parting, conchoidal/uneven, brittle
luster: metallic
system: isometric

Question 16

goethite

Answer 16

color: yellowish/brown to red
streak: yellowish brown
hardness: 5-5.5
fracture: splintery, uneven, botryoidal
luster: vitreous, earthy
system: orthorhombic

Question 17

limonite

Answer 17

color: yellow, brown, red-brown
streak: yellow/brown
hardness: 4-5.5
fracture: splintery/uneven
luster: dull/vitreous or silky
system: amorphous

Question 18

bauxite

Answer 18

color: beige, yellow, red-brown; pastels
streak: white-yellow
hardness: 1-3
luster: dull
system: amorphous

looks like jasper but made of fragments; not a mineral

Question 19

halite

Answer 19

color: colorless/white if pure; otherwise yellow, red, orange, blue, grey, etc.
streak: white
hardness: 2.5
fracture: brittle
cleavage: perfect cubic; conchoidal
luster: vitreous
system: isometric

Question 20

sylvite

Answer 20

color: white, yellow, often red-orange
streak: white
hardness: 2-2.5
fracture: conchoidal
luster: vitreous
system: isometric

Question 21

fluorite

Answer 21

color: clear, purple, blue; possible banding
streak: white
hardness: 4
fracture: conchoidal
cleavage: perfect; 1 on all sides
luster: vitreous
system: isometric