Page 109 - Laboratory Manual in Physical Geology

MINERAL DATABASE (Alphabetical Listing)

Luster and Distinctive
Mineral Crystal Hardness Streak Properties Some Uses
System
CHALCOPYRITE Metallic 3.5–4 Dark gray Color bright silvery gold; Tarnishes Ore of copper, used to
(M) bronze brown, brassy gold, or iridescent make pipes, electrical
CuFeS 2
copper-iron sulfide blue-green and red; Brittle; No cleavage; wire, coins, ammunition,
Forms dense masses or elongate bronze, brass; added to
Tetragonal tetrahedrons; SG = 4.1–4.3 vitamin pills for healthy
hair and skin
CHERT Nonmetallic 7 White* Opaque gray or white; Luster Used as an abrasive;
(NM) waxy; Conchoidal fracture; Used to make glass,
SiO 2
cryptocrystalline No visible SG = 2.5–2.8 gemstones
quartz crystals
CHLORITE Nonmetallic 2–2.5 White Color dark green; Cleavage Used as a “filler” (to take
ferromagnesian (NM) excellent; Forms short prisms up space and reduce
aluminum Monoclinic that split easily into thin cost) in plastics for car
silicate flexible sheets; Luster bright parts, appliances;
or dull; SG = 2–3 Massive pieces carved
(Mg,Fe,Al) 6 (Si,Al) 4 O 10 (OH) 8 into art sculptures
CHROMITE Metallic 5.5–6 Dark brown Color silvery black to black; Tarnishes Ore of chromium for
(M) gray to black; No cleavage; May be chrome, stainless steel,
FeCr 2 O 4
iron-chromium oxide weakly attracted to a magnet; Forms mirrors, yellow and green
dense masses or granular masses of paint pigments and
Isometric small crystals (octahedrons) ceramic glazes, and pills
for healthy metabolism
and cholesterol levels
CHRYSOCOLLA Nonmetallic 2–4 Very light Color pale blue to blue-green; Opaque; Ore of copper, used to
CuSiO 3 · 2H 2 O (NM) blue Forms cryptocrystalline crusts or may make pipes, electrical
hydrated copper be massive; Conchoidal fracture; wire, coins, ammunition,
silicate Orthorhombic Luster shiny or earthy; SG = 2.0–4.0 bronze, brass; added to
vitamin pills for healthy
hair and skin; Gemstone

COPPER Metallic 2.5–3 Copper Color copper; Tarnishes brown or green; Ore of copper, used to
(NATIVE COPPER) (M) Malleable; No cleavage; Forms odd- make pipes, electrical
Cu shaped masses, nuggets, or dendritic wire, coins, ammunition,
copper Isometric forms; SG = 8.8–9.0 bronze, brass; added to
vitamin pills for healthy
hair and skin
CORUNDUM Nonmetallic 9 White* Gray, white, black, or colored (red, blue, Used for abrasive
(NM) brown, yellow) hexagonal prisms with powders to polish lenses;
Al 2 O 3
aluminum oxide flat striated ends; Opaque to gemstones (red ruby,
transparent; Cleavage absent; blue sapphire);
Hexagonal SG = 3.9–4.1 H 9 emery cloth
DOLOMITE Nonmetallic 3.5–4 White Color white, gray, creme, or Ore of magnesium used
(NM) pink; Usually opaque; Cleavage to make paper;
CaMg(CO 3 ) 2
magnesian calcium excellent in 3 directions; Breaks lightweight frames for jet
carbonate into rhombohedrons; Resembles engines, rockets, cell
calcite, but will effervesce in phones, laptops; pills for
dilute HCI only if powdered; good brain, muscle, and
Hexagonal SG = 2.8–2.9 skeletal health
EPIDOTE Nonmetallic 6–7 White* Color pale or dark green to Used as a green
complex silicate (NM) yellow-green; Massive or forms gemstone
striated prisms; Cleavage poor;
Monoclinic SG = 3.3–3.5
FELDSPAR: See PLAGIOCLASE (Na-Ca Feldspars) and POTASSIUM FELDSPAR (K-Spar)

FLINT Nonmetallic 7 White* Color black to very dark gray; Used as an abrasive;
(NM) Opaque to translucent; Used to make glass;
SiO 2
cryptocrystalline No visible Conchoidal fracture; Crypto- Black gemstone
quartz crystals crystalline; SG = 2.5–2.8
FLUORITE Nonmetallic 4 White Colorless, purple, blue, gray, Ore of fluorine used in
(NM) green, or yellow; Cleavage fluoride toothpaste,
CaF 2
calcium fluoride excellent; Crystals usually refrigerant gases, rocket
cubes; Transparent or fuel
Isometric opaque; Brittle; SG = 3.0–3.3
*Streak cannot be determined with a streak plate for minerals harder than 6.5. They scratch the streak plate.
FIGURE 3.21 (continued)

94 ■ L ABOR ATORY 3