Minerals

Question 1

Brass color, H 6-6.5, conchoidal to uneven fracture that creates cubes, Dark or grey streak

Answer 1

Pyrite

Question 2

Silvery grey to black color, H 6-6.5, strongly attracted to a magnet, fracture

Answer 2

Magnetite

Question 3

Color silvery black to black; tarnishes gray to black; H 5.5–6; maybe weakly attracted to a magnet; forms octahedrons, absent cleavage

Answer 3

Chromite

Question 4

Color steel gray, reddish-silver, to glittery bright silver (var. specular); both metallic varieties have the characteristic red-brown streak; may be attracted to a magnet; H 5–6; also occurs in nonmetallic, dull to earthy, red to red-brown streak

Answer 4

Hematite

Question 5

Color bright silvery gray; tarnishes dull gray; brittle: breaks into cubes and shapes made of cubes; H 2.5; forms cubes or octahedrons; feels heavy for its size because of high specific gravity

Answer 5

Galena

Question 6

Color bright silvery gold; tarnishes bronze brown brassy gold, or iridescent blue-green and red; H 3.5–4.0; brittle; uneven fracture; forms tetrahedrons

Answer 6

Chalcopyrite

Question 7

Color opaque brassy to brown-bronze; tarnishes dull brown, may have faint iridescent colors; fracture uneven to conchoidal; no cleavage; attracted to a magnet; H 3.5–4.5; usually massive or masses of tiny crystals; resembles chalcopyrite, which is softer and not attracted to a magnet

Answer 7

Pyrrhotite

Question 8

Color dark silvery gray to black; can be scratched with your fingernail; easily rubs off on your fingers and clothes, making them gray; H 1–2

Answer 8

Graphite

Question 9

Metallic or silky submetallic luster, color dark brown, gray, or black; H 5–5.5; forms layers of radiating microscopic crystals and botryoidal masses

Answer 9

Goethite

Question 10

Color copper; tarnishes dull brown or green; H 2.5–3.0; malleable and sectile; hackly fracture; usually forms dendritic masses or nuggets

Answer 10

Copper

Question 11

Translucent to opaque dark gray; blue-gray, or black; may have silvery iridescence; 2 cleavages at nearly 90° and with striations; H 6

Answer 11

Plagioclase feldspar

Question 12

Translucent to opaque dark gray; blue-gray, or black; may have silvery iridescence; 2 cleavages at nearly 90° and with striations; H 6

Answer 12

Potassium feldspar

Question 13

Transparent or translucent gray, brown, or purple; vitreous luster; massive or hexagonal prisms and pyramids; H 7, absent cleavage

Answer 13

Quartz

Question 14

Gray, black, or colored (dark red, blue, brown) hexagonal prisms with flat striated ends; H 9, absent cleavage

Answer 14

Corundum

Question 15

Transparent to translucent dark red to black; equant (dodecahedron) crystal form or massive; H 7

Answer 15

Garnet

Question 16

Black or dark green; long striated prisms; H 7–7.5

Answer 16

Tourmaline

Question 17

Olive green, transparent or translucent; no cleavage; usually has many cracks and conchoidal to uneven fracture; single crystals or masses of tiny crystals resembling green granulated sugar or aquarium gravel; the crystals have vitreous (glassy) luster

Answer 17

Olivine

Question 18

Opaque green; poor cleavage; H 6–7

Answer 18

Epidote

Question 19

Purple cubes or octahedrons; octahedral cleavage; H 4

Answer 19

Fluorite

Question 20

Black short opaque prisms; splits easily along 1 excellent cleavage into thin sheets; H 2.5–3

Answer 20

Biotite

Question 21

Green short opaque prisms; splits easily along 1 excellent cleavage into thin sheets; H 2–3

Answer 21

Chlorite

Question 22

Deep blue; crusts, small crystals, or massive; light blue streak; H 3.5–4

Answer 22

Azurite

Question 23

Green, green-blue, gray, yellow-green, white; platy or tabular or fibrous (chrysotile asbestos); H 2.5–3.5

Answer 23

Serpentine Minerals

Question 24

Opaque green in laminated crusts or massive; streak pale green; effervesces in dilute HCI; H 3.5–4

Answer 24

Malachite

Question 25

Translucent or opaque dark green; can be scratched with your fingernail; feels greasy or soapy; H 1

Answer 25

Talc

Question 26

Transparent or translucent green, brown, blue, or purple; brittle hexagonal prisms; conchoidal fracture; H 5

Answer 26

Apatite

Question 27

Opaque earthy brick red to dull red-gray, or gray; H 1.5–5; red-brown streak; magnet may attract the gray forms

Answer 27

Hematite

Question 28

Colorless, white, yellow, green, pink, or brown; 3 excellent cleavages; breaks into rhombohedrons; effervesces in dilute HCI; H 3

Answer 28

Calcite

Question 29

Colorless, white, yellow, blue, brown, or red; cubic crystals; breaks into cubes; salty taste; H 2.5

Answer 29

Halite

Question 30

Opaque pale blue to blue-green; conchoidal fracture; H 2–4; massive or amorphous earthy crusts; very light blue streak

Answer 30

Chrysocolla