Lab 1: Minerals (Characteristics)

Pyrite

• metallic luster

• shiny gold color

• cubic crystals

• dark streak

• heavy (dense)

Galena

• metallic luster

• silver color

• heavy (dense)

• 3 directions of cleavage at 90 degrees

• black streak

Talc

• pearly white to pale green

• can be scratched with a fingernail

• soapy feel

calcite

• clear to white

• 3 directions of cleavage not at 90 degrees

• can be scratched with a penny

• fizzes in acid

halite

• clear

• 3 directions of cleavage at 90 degrees

• tastes salty

quartz

• clear

• can have prismatic crystal (hexagonal)

• scratches glass

• no cleavage (fracture)

olivine

• yellow-green color

• glassy luster

• fracture

hematite

• reddish brown streak

• dull dusty red color OR metallic luster

• silver color

magnetite

• magnetic

• black

• dull (metallic luster on fresh surface)

• dense

• dark streak

potassium feldspar

• pink color

• striations

• 2 directions of cleavage at 90 degrees

• can scratch glass

plagioclase feldspar

• silvery white color

• 2 directions of cleavage at 90 degrees

• can scratch glass

garnet

• greenish yellow

• 12-sided (dodecahedral) crystals

• scratches glass

augite

• black

• 2 directions of cleavage at 90 degrees

• white streak

sulfur

• yellow

• smells like eggs

• no cleavage

gypsum

• white

• striated

• can be scratched with a fingernail

biotite mica

• black

• one direction of cleavage (peels into sheets)

• scratch with fingernail

muscovite mica

• silvery grey

• one direction of cleavage (peels into sheets)

• scratch with fingernail

graphite

• dull metallic luster

• silvery grey streak

• greasy feel

• writes on paper

kaolinite

• soft, powdery appearance

• sticks to finger when wet

corundum

• dark red color

• can scratch glass and all the other minerals

• hexagonal crystals

copper

• copper color

• metallic luster