GLG 103 Lab 2 Exam Questions with Verified
Correct Answers
amphibole group (hornblende)
black brown, to dark green, translucent to opaque, hardness 6, specific gravity 3.0-2.4,
vitreous luster, white streak, 2 good cleavage directions, in igneous an metamorphic rocks
Azurite
blue color, associated with limonite and malachite, copper carbonate hydroxide, 3.5-4
hardness, 3.8 specific gravity, vitreous to dull luster, blue streak, brittle
Barite
barium sulfate, tabular shape, sometimes forms 'roses', colorless, white, light blue or yellow,
golden brown, hardness 3-3.5, 4.3-4.6 specific gravity, vitreous, white streak, good prismatic
cleavage, found with limestone
Biotite
perfect 'micaceous' cleavage in flat and smooth surfaces (one direction), black to very dark
brown, hardness 2.5-3, specific gravity 2.8 - 3.2, vitreous or splendent, brownish streak
calcite
calcium carbonate, clear to variety of color, double refraction, transparent to opaque,
hardness 3, specific gravity 2.72, vitreous to earthy, white streak, 3 directions perfect
cleavage, reacts to HCl
Chalcopyrite
copper iron sulfide, brass yellow to dark brown, opaque, hardness 3.5 -4, specific gravity 4.2-
4.3, metallic luster, black streak, one poor cleavage direction
, Copper
copper luster and color, opaque, hardness 2.5-3, specific gravity 8.9, metallic luster, copper
streak,
dolomite
calcium magnesium carbonate, curved crystals, pinkish, clear, gray to black, hardness 3.5-4,
specific gravity 2.85, vitreous to dull luster, white streak, powdered forms reacts to HCl
Fluorite
subdued colors, calcium fluoride, transparent to translucent, sometimes fluorescent, hardness
4, specific gravity 3.17-3.56, vitreous to dull, white streak, very good cleavage, dodecahedral
faces
growth hillcocks
irregular growths on crystal faces
galena
lead sulfide, cubic cleavage, bright silver to dull gray, hardness 2.5, specific gravity 7.4-7.6,
metallic luster, lead gray streak
garnet
multiple species, commonly red but also more colors, transparent to translucent, hardness 6.5-
7.5, specific gravity 3.5-4.3, vitreous to resinous, white streak
Gold
golden color, opaque, hardness 2.5-3, specific gravity 19.3, metallic luster, gold streak
graphite
Correct Answers
amphibole group (hornblende)
black brown, to dark green, translucent to opaque, hardness 6, specific gravity 3.0-2.4,
vitreous luster, white streak, 2 good cleavage directions, in igneous an metamorphic rocks
Azurite
blue color, associated with limonite and malachite, copper carbonate hydroxide, 3.5-4
hardness, 3.8 specific gravity, vitreous to dull luster, blue streak, brittle
Barite
barium sulfate, tabular shape, sometimes forms 'roses', colorless, white, light blue or yellow,
golden brown, hardness 3-3.5, 4.3-4.6 specific gravity, vitreous, white streak, good prismatic
cleavage, found with limestone
Biotite
perfect 'micaceous' cleavage in flat and smooth surfaces (one direction), black to very dark
brown, hardness 2.5-3, specific gravity 2.8 - 3.2, vitreous or splendent, brownish streak
calcite
calcium carbonate, clear to variety of color, double refraction, transparent to opaque,
hardness 3, specific gravity 2.72, vitreous to earthy, white streak, 3 directions perfect
cleavage, reacts to HCl
Chalcopyrite
copper iron sulfide, brass yellow to dark brown, opaque, hardness 3.5 -4, specific gravity 4.2-
4.3, metallic luster, black streak, one poor cleavage direction
, Copper
copper luster and color, opaque, hardness 2.5-3, specific gravity 8.9, metallic luster, copper
streak,
dolomite
calcium magnesium carbonate, curved crystals, pinkish, clear, gray to black, hardness 3.5-4,
specific gravity 2.85, vitreous to dull luster, white streak, powdered forms reacts to HCl
Fluorite
subdued colors, calcium fluoride, transparent to translucent, sometimes fluorescent, hardness
4, specific gravity 3.17-3.56, vitreous to dull, white streak, very good cleavage, dodecahedral
faces
growth hillcocks
irregular growths on crystal faces
galena
lead sulfide, cubic cleavage, bright silver to dull gray, hardness 2.5, specific gravity 7.4-7.6,
metallic luster, lead gray streak
garnet
multiple species, commonly red but also more colors, transparent to translucent, hardness 6.5-
7.5, specific gravity 3.5-4.3, vitreous to resinous, white streak
Gold
golden color, opaque, hardness 2.5-3, specific gravity 19.3, metallic luster, gold streak
graphite
