Minerals Quiz GEOL 110L

Galena

• SG is heavy

• Between glass and fingernail

• 3D rhombohedral cleavage

• Metallic gray streak

• Shiny, metallic gray

Halite

• Betweeen glass and fingernail

• 3D rhombohedral cleavage

• No streak

• Glassy, transparent, any color tint

Olivine

• Harder than glass

• No cleavage

• No streak

• Sparkly green

Muscovite

• Flexible in thin sheets

• Softer than fingernail, flakes off

• 1D basal cleavage, can peel apart

• Orangish-white streak

• Pearly, clear/brown but can be any color

Calcium plagioclase feldspar

• Striations, DARK

• SG is pretty light

• Harder than glass

• 2D prismatic parallelogram cleavage

• No streak

• Glassy, metallic dark gray

Garnet

• Harder than glass

• No cleavage

• Red-yellow-brown streak

• Glassy, red but can be any color

Graphite

• Pencil filling

• Softer than fingernail

• No cleavage

• Metallic gray streak

• Shiny, metallic gray

Quartz

• Harder than glass

• No cleavage

• No streak

• Sparkly or glassy, transparent and can be any color

Pyrite

• Harder than glass

• No cleavage

• Black streak

• Sparkly, metallic gold

Biotite

• Flexible in thin sheets

• Between glass and fingernail

• 1D basal cleavage

• No streak

• Glassy, green-brown-black

Sodium plagioclase feldspar

• Striations, LIGHT

• Harder than glass

• 2D prismatic parallelogram cleavage

• No streak

• Dull, bit sparkly, white-gray

Amphibole

• Harder than glass

• No cleavage

• Gray-green streak

• Shiny, black or white or green

Magnetite

• Attracted to magnet

• Harder than glass

• No cleavage

• No streak

• Dull, bit sparkly, black but rusts orange

Pyroxene

• Harder than glass

• 2D prismatic parallelogram cleavage

• No streak

• Dull, green-black

Kaolinite

• Softer than fingernail

• No cleavage

• White streak

• Dull, white/tan

Potassium feldspar

• Harder than glass

• 2D prismatic parallelogram cleavage

• Pearly, orange-pink-brown

Hematite

• Round bumps

• Harder than glass

• No cleavage

• Red streak

• Dull OR sparkly, red-brown-gray

Calcite

• Acid reaction, fizzes at HCl

• Between glass and fingernail

• 3D rhombohedral cleavage

• White streak

• Glassy, translucent but can be any color

Talc

• Softer than fingernail

• No cleavage

• White streak

• Pearly, white

Gypsum

• Softer than fingernail

• 1D basal cleavage

• No streak

• Glassy/pearly, clear

Dolomite

• Between glass and fingernail

• 3D rhombohedral cleavage

• White streak

• Sparkly, white-gray