Lab 1 // Minerals Part 1

Question 1

Quartz

nonferromagnesian silicate

Answer 1

Luster: Greasy (nonmetallic)
Hardness: 7
Color: Transparent white, pink, purple, grey etc. White streak (but too hard).
Fractures: Conchoidal
Properties: Forms hexagonal prism ending in a pyramids
Used as: abrasive, to make glass, gemstones (amethyst - purple quartz)

Question 2

Calcite

Carbonate

Answer 2

Luster: nonmetallic
Hardess: 3 (2.5-5.5)
Color: transparent white, etc. with whitish streak
Fractures: 3 cleavage not @ 90º (rhombic)
Properties: Effervesces (reacts forming bubbles) readily with dilute HCl.
Used as: antacids, fertilizer, cement, and a source for calcium.

Question 3

Mica group:
Biotite
(ferromagnesian silicate)
Muscovite
(nonferromagnesian silicate)

Answer 3

Luster: nonmetallic (or slightly metallic)
Hardness: around 2.5 (your fingernail may not scratch it)
Colour/Streak:
-Biotite - black/goldish (too flaky to streak)
-Muscovite - translucent/goldish
Cleavage/Fracture: 1 (basal) cleavage, irregular fracture along edges)
Properties: elastic tenacity - you can bend it and when you release the pressure it returns to the original shape
How it is used:
-Biotite - used for fire-resistant tiles, rubber, paint
-Muscovite - electrical insulation and cosmetics

Question 4

Magnetite

Oxide

Answer 4

Luster: metallic
Hardness: 5.5-6.5
Colour/Streak: silvery black with black or dark greyish streak
Cleavage/Fracture: too difficult to see how individual grains break
Properties: magnetic
How it is used: an ore of iron (important for making steel)

Question 5

Talc

nonferromagnesian silicate

Answer 5

Luster: nonmetallic
Hardness: 1
Colour/Streak: white with white streak
Cleavage/Fracture: too difficult to see how the individual grains break
Properties: soapy feel
How it is used: used as an inexpensive filler in plastics, large pieces caned as sculptures

Question 6

Olivine

ferromagnesian silicate

Answer 6

Luster: nonmetallic
Hardness: H > 6,5
Colour/Streak: translucent green
Cleavage/Fracture: conchoidal
Properties: Typically seen as an aggregate (rock) consisting of sugar-sized grains
How it is used: used as a gemstone (green peridot), a source for magnesium

Question 7

Dolomite

carbonate

Answer 7

Luster: nonmetallic
Hardness: H > 2.5-5.5
Colour/Streak: transparent, white, other colours possible with whitish streak
Cleavage/Fracture: 3 not @ 90º (rhombic)
Properties: Effervesces with HCl but only when powdered (more surface area for a quicker reaction)
How it is used: used as a source for magnesium

Question 8

Sphalerite

sulphide

Answer 8

Luster: both nonmetallic and metallic
Hardness: 2.5-5.5
Colour/Streak: dark colour with light yellow streak
Cleavage/Fracture: 6 cleavage not @ 90º (hard to see all 4 though)
Properties: -
How it is used:used as an ore of zinc (for brass, galvanized steel, skinhealing creams, etc.)