Sulfides - Identification and Characteristics (Meta)

Question 1

Chalcocite

Answer 1

Hardness 2-3, Tabular/pseudohexagonal crystals, Metallic luster, Gray to black color, Dark gray streak (may be shiny)

Question 2

Cinnabar

Answer 2

Hardness 2-2.5, Hexagonal tabular crystals, Often intergrown or penetration twins, Adamantine to dull luster, Red color, Red streak

Question 3

Covellite

Answer 3

Hardness 1.5-2, Rare hexagonal tabular crystals, Dark metallic-blue to dark gray and iridescent color, Metallic luster, Dark gray to black streak

Question 4

Galena

Answer 4

Hardness 2.5-3, Perfect isometric crystals (cubes, octahedrons, or both), Steel gray streak and color

Question 5

Marcasite

Answer 5

Hardness 6-6.5, Smells like sulfur, Pale brass-yellow to nearly white (can tarnish brown and/or iridescent), Dark brown to nearly black streak, Orthorhombic and frequently coxcomb crystals

Question 6

Molybdenite

Answer 6

Hardness 1-1.5, Silver to lead-gray, Thin/platy hexagonal crystals that can be easily moved and bent out of shape, Gray to grayish-black streak, Metallic luster

Question 7

Orpiment

Answer 7

Hardness 1.5-2, Yellow streak, Often bright yellow but can be [bright] orange-ish or brown, Often occurs with Realgar

Question 8

Pyrite

Answer 8

Hardness 6-6.5, Black streak with greenish tinge, Metallic luster, No cleavage

Question 9

Pyrrhotite

Answer 9

Hardness 3.5-4.5, Usually bronze color, Metallic luster, Usually pseudohexagonal crystals, Magnetic (extent depends on iron deficiency, more with less iron)

Question 10

Realgar

Answer 10

Hardness 1.5-2, Bright red color, Orange to reddish-orange streak, Adamantine to resinous to dull luster, Prismatic and stubby crystals that are heavily striated lengthwise

Question 11

Sphalerite

Answer 11

Hardness 3.5-4, Really any color, White-brown streak (always lighter than specimen), Really any luster but rarely transparent b/c Fe impurities

Question 12

Stibnite

Answer 12

2 Hardness, Metallic silver-gray color, Long slender crystals, Dark gray streak

Question 13

Arsenopyrite

Answer 13

5.5-6.5 Hardness, Metallic luster, Silver-white to steel gray-color, Distinct prismatic crystals often twinned and triangular

Question 14

Bornite

Answer 14

3-3.5 Hardness, Metallic luster, Copper-red to yellowish brown on fresh surface but quickly tarnishes to multicolored purple blue and red, No discernable cleavage

Question 15

Chalcopyrite

Answer 15

3.5-4 Hardness, Metallic luster, Brass-yellow to golden-yellow color, Tarnishes to multicolored blue purple and red, Tetragonal crystals {Looks somewhat like pyrite but won’t scratch glass}

Question 16

Enargite

Answer 16

3 Hardness, Steel gray to black color and streak, Perfect cleavage, Prismatic and tablular crystals with flattened terminations