Lab 2 // Minerals Part 2 Flashcards
Flourite (CaF2)
halide
Luster: nonmetallic
Hardness: 2.5-5.5 (4)
Colour/Streak: translucent green, blue, purple, yellow, etc. (with whitish streak)
Cleavage/Fracture: 4 not @ 90º, conchoidal fracture
Properties: Many cleavage fragments have triangular faces (only can be made by breaking something with 4 cleavages)
How it’s used: a source of flourine (for toothpaste. rocket fuel, etc.)
Hematite (Fe2O3)
oxide
Luster: metallic
Hardness: 5.5-6.5
Colour/Streak: silver, grey (with reddish-brown streak)
Cleavage/Fracture: n/a (too difficult to see how individual grains break)
Properties: Note there are two samples; flaky metallic and earthy
How it’s used: an ore of iron, a red ochre pigment in paint and cosmetics, medicine
Halite (NaCl)
halide
Luster: nonmetallic
Hardness: 2.5-5.5
Colour/Streak: transparent (with whitish streak)
Cleavage/Fracture: 3 @ 90º (cubic cleavage)
Properties: salty taste
How it’s used: table salt, road salt, water softeners, and as a preservatives, source of sodium
Galena (PbS)
sulphide
Luster: metallic
Hardness: 2.5-5.5
Colour/Streak: bluish-silver (with bluish-silver/grey streak)
Cleavage/Fracture: 3 @ 90º (cubic cleavage)
Properties: high specific gravity (heavy mass for its size)
How it’s used: an ore of lead (tv glass, auto batteries, etc.)
Pyrite (FeS2)
sulphide
Luster: metallic
Hardness: 5.5-6.5
Colour/Streak: brassy gold (with black/greyish streak)
Cleavage/Fracture: conchoidal fracture
Properties: if the sample is a crystal. the crystal form is either that of dodecahedrons or cubes)
How it’s used: an ore of sulphur (fertilizer, matches, gunpowder, etc.)
Chalcopyrite (CuFeS2)
sulphide
Luster: metalic
Hardness: 2.5-5.5
Colour/Streak: orangish, greenish gold (spray paint gold) (with greyish streak)
Cleavage/Fracture: n/a (too difficult to see how individual grains break)
Properties: -
How it’s used: an ore of copper (pipes, electrical wire, coins, etc.)
Gypsum (CaSO4·H2O)
sulphate
Luster: nonmetallic
Hardness: H < 2.5 (2)
Colour/Streak: transparent, can be coloured as well (with whitish streak)
Cleavage/Fracture: 1 (basal) - but not in thin sheets, conchoidal fracture around edges
Properties: a very soft mineral, but without the soapy feel that talc has
How it’s used: make plaster-of-Paris wallboard, drywall, and art sculpture
Amphibole (hornblende, formula with Ca & Al)
ferromagnesian silicate
Luster: nonmetallic
Hardness: 5.5-6.5
Colour/Streak: dark green with whitish streak
Cleavage/Fracture: 2 not @ 90º
Properties: amphibole typically breaks into long, slender shapes with cleavage directions easy to see
How it’s used: (fibrous varieties) in making fire resistant clothing, tiles, and brake linings
Pyroxene (augite, long formula with Ca)
ferromagnesian silicate
Luster: nonmetallic
Hardness: 5.5-6.5
Colour/Streak: dark green (with whitish streak)
Cleavage/Fracture: 2 @ 90º (though only one may be visible), uneven/irregular fracture
Properties: Pyroxene typically breaks in blocky shapes with cleavage (cleavage not easily seen)
How it’s used: a source of lithium (lithium batteries, treatment of depression)
a) K-spar (orthoclase, KAlSi3O8)
b) Na-rich Plag (albite, NaAlSi3O8)
c) Ca-rich Plag (labradorite)
nonferromagnesian silicate
Luster: nonmetallic
Hardness: 5.5-6.5 (6)
Colour/Streak: salmon pink, marble-like white, bluish grey (with whitish streak)
Cleavage/Fracture: 2 @ 90º, uneven/irregular fracture
Properties:
- a: exsolution lamellae visible
- b and c: striations visible
How it’s used: ceramics, glass, enamel, soap, false teeth, scouring powders
