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Flashcards in MINERAL MIDTERM Deck (46)
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1

  • Pyrite
  • FeS2
  • Streak is greenish-black
  • Conchoidal fracture
  • Hardness 6-6.5
  • SG is approx 5.1 (heavier than most emtallic minerals)

2

  • Marcasite
  • FeS2
  • Streak is greenish to brownish-black
  • Sometimes a faintly decectable sulfur smell
  • Color is brassy yellow with a greenish tint
  • multi-color tarnish may be present

3

Pyrrohotite

  • Fe(1-x)S (x=0 to 0.2)
  • Color is bronze
  • Luster is metallic
  • Hardness is 3.5 - 4.5
  • Streak is grey-black
  • Weakly magnetic

4

Covellite

  • Covellite
  • CuS
  • Color is deep metallic indigo blue (tarnished purple-black) w/ irridescent flashes of yellow and red
  • Cleavage is perfect in one direction forming thin, flexible sheets
  • Fracture is flaky
  • Hardness is 1.5 - 2
  • SG is 4.6 - 4.8
  • Streak is grey to black

5

Chalcocite

  • Cu2S
  • Chalcocite
  • Color is dark grey to black
  • Xtals are usually deeply grooved/striated
  • Cleavage is perfect in 2 directions, prismatically
  • Fracture is conchoidal
  • Hardness is 2.5 - 3
  • Streak is shiny black to grey

6

  • Chalcopyrite
  • CuFeS2
  • Color is brassy yellow, tarnishes to irridescent blues, greens, yellows, and purples
  • Cleavage is rather poor in 1 direction
  • Hardness is 3.5 - 4
  • Streak is dark green

7

  • Bornite
  • Cu5FeS4
  • Color is brown to black with a typical purplish-bluish tarnish, a reddish bronze color on freshly broken surfaces
  • Cleavage is very poor
  • Fracture is conchoidal
  • Hardness is 3
  • Streak is grey-black

8

  • Sphalerite
  • (Zn, Fe)S
  • Color is typically black but can be brown, yellow, reddish, green, and less commonly white or colorless
  • Luster is adamantine or resinous or submetallic to earthy
  • Cleavage is perfect in 6 directions forming dodecahedrons
  • Fracture is conchoidal but rarely seen
  • Hardness 3.5 - 4
  • Streak is yellow to light brown 
  • triboluminescence 
  • Pyroelectric

9

  • Galena
  • PbS
  • Color is lead to silver grey sometimes with a bluish tint
  • Habits include cubes, octahedron, and combos
  • Cleavage is perfect in 4 directions
  • Fracture is uneven
  • Hardness 2.5+
  • SG is 7.5+ (especially heavy)
  • Streak is lead grey

10

  • Cinnabar
  • HgS
  • Color is bright scarlet or cinnamon red to a brick red
  • Luster is adamantine to submetallic
  • Hardness is 2 - 2.5
  • SG is 8.1+ (especially heavy for non-metallic mineral)
  • Habits are rarely individual xtal, commonly crusts and massive

11

  • Realgar
  • As4S4
  • Color is orange to red
  • Luster is resinous, adamantine, to submetallic
  • Cleavage is good in 1 direction
  • Hardness is 1.5 - 2
  • Streak is orange-yellow
  • Unstable in light
  • Almost always inclue orpiment

12

  • Orpiment
  • As2S3
  • Color is orange-yellow to yellow
  • Hardness is 1.5 - 2
  • Streak is yellow
  • Unstable in light
  • Distinct odor similar to sulfur but due to the aresenic

13

  • Stibnite
  • Sb2S3
  • Color is steel grey to silver
  • Luster is metallic
  • Cleavage is perfect in lengthwise direction
  • Streak is dark grey
  • Striated lengthwise
  • Slightly flexible xtals

14

  • Molybdenite
  • MoS2
  • Color is silver metallic with a bluish cast
  • Luster is metallic
  • Cleavage is perfect in 1 direction, forming sheets
  • Fracture is flaky
  • Hardness is 1.5 - 2
  • Streak is bluish grey

15

  • Arsenopyrite
  • FeAsS
  • Color is brassy white to grey
  • Luster is metallic
  • Hardness is 5.5 - 6
  • SG is approx 6.1 (slightly heavier than usual)
  • Bitter smell when powdered or broken

16

  • Tetrahedrite
  • (Cu, Fe)12Sb4S13
  • Color is black to steel grey to silver
  • Luster is metallic
  • No cleavage
  • Fracture is conchoidal
  • Hardness is 3 - 4+
  • Tarnishes to greenish shade

17

  • Kernite
  • Na2B4O6(OH)2 3H2O
  • Color is colorless to white
  • Luster is vitreous to pearly
  • Cleavage is perfect in 2 directions
  • Fracture is splintery due to cleavage
  • SG is 1.9 (very low density)
  • Streak is white

18

  • Borax
  • Na2[B4O5(OH)4] 8H2O
  • Color is white
  • Luster is dull/earthy
  • Cleavage is perfect in 1 direction
  • Fracture is conchoidal
  • Hardness is 2 - 2.5
  • SG is 1.7 (very light density)
  • Streak is white
  • Sweet alkaline taste

19

  • Gold
  • Au
  • Streak is golden yellow
  • SG is 19.3+ (very heavy)
  • Ductile, sectile, and malleable
  • Native element

20

  • Silver
  • Ag
  • Streak is silver white
  • Hardness is 2.5 - 3
  • Ductile, sectile, malleable
  • Native element

21

  • Copper
  • Cu
  • Native element
  • Streak is reddish copper
  • Ductile, sectile, malleable

22

  • Sulfur
  • S
  • Native element
  • Cleavage is poor in 2 directions
  • Odor
  • Poor heat conductivity
  • Massive or powdery habits

23

  • Diamond
  • C
  • Native element
  • Color is variable, tends toward pale yellow and brown
  • Luster is adamantine to waxy
  • Hardness is 10
  • Cleavage is perfect in 4 directions
  • Streak is white

24

  • Graphite
  • C
  • Native element
  • Habit includes massve lamellar veins and earthy masses
  • Cleavage is perfect in 1 direction
  • Thin flakes are flexible but inelastic

25

  • Halite
  • Habit is predominantly cubes
  • Cleavage is perfect in 3 directions forming cubes
  • Fracture is conchoidal
  • SG is 2.1 (light)
  • Hardness is 2
  • Salty taste

26

  • Sylvite
  • Cleavage is good in 3 directions
  • Hardness is 2 - 2.5
  • SG is 3.9 - 4.1 (heavier than average for translucent)
  • Dissolves easily in water
  • Bitter taste
  • Does not powder easily

27

  • Fluorite
  • Cleavage is eprfect in 4 directions forming octahedrons
  • Fracture is irregular and brittle
  • Hardness is 4
  • Often fluoresces
  • Color zoning

28

  • Corundum
  • Al2O3
  • Luster adamantine to vitreous
  • All colors
  • Parting occurs in 3 directions
  • Hardness 9
  • Streak is white
  • EXTREME hardness

29

  • Fe2O3
  • Color is metallic grey, dull to bright red
  • Parting in 2 directions
  • Hardness is 5 - 6
  • SG is 5.3 (slightly above)
  • Streak is red******

30

  • Ilmenite
  • FeTiO3
  • Color is iron black, grey w/brownish tint
  • Hardness is 5 - 6
  • Streak is black
  • No cleavage