Mineral Identification Lab Answers

Question: Calcite (1)

Answer: Comes in many white colorsWhite streakHardness = 33 directions of cleavage not at 90 degreesNonmetallic-glassy lusterReacts to HCl

Question: Quartz (2)

Answer: Many light colorsNo streakHardness = 7Conchoidal fractureNonmetallic-glassy lusterLarge crystals are elongate and may have 6 facets but are not cleavage planes

Question: Garnet (3)

Answer: Deep reddish purpleNo streakHardness = 8Conchoidal fractureNonmetallic-glassy lusterWell-formed crystals are spherical with many facets that are not cleavage planes

Question: Amphibole (4)

Answer: BlackGreenish-black streakHardness = 62 cleavages not at 90 degreesNonmetallic-glassy luster

Question: Pyroxene (5)

Answer: Much like amphibole in its physical propertiesDiffers mainly in cleavage: 2 cleavages at 90 degrees

Question: Olivine (6)

Answer: Olive green colorNo streakHardness = 6Conchoidal FractureNonmetallic-glassy lusterTiny grains, need hand-lens

Question: Muscovite Mica (7)

Answer: Silver or golden when in thick sheetsClear when in thin sheetsWhite streakHardness = 2One excellent cleavageNonmetallic-glassy or plastic-like

Question: Biotite Mica (8)

Answer: Brown or dark greenBrownish or greenish streakWhite streakHardness = 2One excellent cleavageNonmetallic-glassy or plastic-like

Question: Feldspar, K-rich (9)

Answer: Pinkish colorNo streak Hardness = 62 cleavages at 90 degreesNonmetallic-glassy luster

Question: Feldspar, Na- and Ca-rich (10)

Answer: White samples are Na-richDark samples are Ca-richHardness = 62 cleavages at 90 degreesNonmetallic-glassy luster

Question: Talc (11)

Answer: Many (usually light) colorsWhite streakHardness = 1One poor cleavageNonmetallic-pearly lusterThe source of talcum power

Question: Pyrite (12)

Answer: Brass yellow colorDark streakHardness = 6 (varies)Conchoidal fractureMetallic lusterSome samples have cubic crystalsOre is made of iron and sulfurFool's gold

Question: Chalcopyrite (13)

Answer: Greenish brass yellow colorDark streakHardness = 4 (variable)No cleavage and no crystalsMetallic lusterOre contains iron and sulfur plus copper (chalco means copper)Fool's gold

Question: Sphalerite (14)

Answer: Brownish colorYellow streakHardness = 3.5-4Many cleavages at various anglesNonmetallic "resinous" or metallicContains zinc, iron, and sulfur

Question: Galena (15)

Answer: Dark grey Dark streakHardness = 5-63 cleavages at 90 degrees (called cubic cleavage)Metallic lusterUnusually heavyLead ore, contains lead and sulfur

Question: Hematite (16)

Answer: Red, black, and silvery varietiesRed-brown streakHardness = 5-6No cleavageMetallic lusterIron ore, contains iron and oxygen