Mineral Identification Lab

Comes in many white colors White streak Hardness = 3 3 directions of cleavage not at 90 degrees Nonmetallic-glassy luster Reacts to HCl

Many light colors No streak Hardness = 7 Conchoidal fracture Nonmetallic-glassy luster Large crystals are elongate and may have 6 facets but are not cleavage planes

Deep reddish purple No streak Hardness = 8 Conchoidal fracture Nonmetallic-glassy luster Well-formed crystals are spherical with many facets that are not cleavage planes

Black Greenish-black streak Hardness = 6 2 cleavages not at 90 degrees Nonmetallic-glassy luster

Much like amphibole in its physical properties Differs mainly in cleavage: 2 cleavages at 90 degrees

Olive green color No streak Hardness = 6 Conchoidal Fracture Nonmetallic-glassy luster Tiny grains, need hand-lens

Silver or golden when in thick sheets Clear when in thin sheets White streak Hardness = 2 One excellent cleavage Nonmetallic-glassy or plastic-like

Brown or dark green Brownish or greenish streak White streak Hardness = 2 One excellent cleavage Nonmetallic-glassy or plastic-like

Pinkish color No streak Hardness = 6 2 cleavages at 90 degrees Nonmetallic-glassy luster

White samples are Na-rich Dark samples are Ca-rich Hardness = 6 2 cleavages at 90 degrees Nonmetallic-glassy luster

Many (usually light) colors White streak Hardness = 1 One poor cleavage Nonmetallic-pearly luster The source of talcum power

Brass yellow color Dark streak Hardness = 6 (varies) Conchoidal fracture Metallic luster Some samples have cubic crystals Ore is made of iron and sulfur Fool's gold

Greenish brass yellow color Dark streak Hardness = 4 (variable) No cleavage and no crystals Metallic luster Ore contains iron and sulfur plus copper (chalco means copper) Fool's gold

Brownish color Yellow streak Hardness = 3.5-4 Many cleavages at various angles Nonmetallic "resinous" or metallic Contains zinc, iron, and sulfur

Dark grey Dark streak Hardness = 5-6 3 cleavages at 90 degrees (called cubic cleavage) Metallic luster Unusually heavy Lead ore, contains lead and sulfur

Red, black, and silvery varieties Red-brown streak Hardness = 5-6 No cleavage Metallic luster Iron ore, contains iron and oxygen