EAS 210: Chapter 2 Key Terms

Amphibole

-2 cleavage planes at 60 and 120 degrees
- Hardness of 6
-Dark green to Black
-long, primsatic 6-sided crystals
-vitreous to dull lustre
-stepped cleavage faces
-Double Chain

Biotite

-Vitreous Lustre
-may have faint brown-grey streak
-Perfect mica cleavage
-1 cleavage plane
-Black to brownish
Hardness of 2.5-3

Calcite

-Reacts with HCL
-3 Perfect cleavages at 75 degrees
- Hardness of 3
- Double refraction and transparent-opaque
-Vitreous lustre

Chalcopyrite

-Goldenyellow or greenish yellow in colour
- No cleavage
-Black streak
-Massive
-Hardness of 3.5-4
-CuFeS2

Dolomite

- 3 cleavages at 75 degrees
-Reacts slowly with HCl unless powdered
- Vitreous lustre
-Small rhombic crystals
-Colourless, white, yellow, rarely, gray and blue
Hardness of 3.5-4

Galena

-Dull and Greasy lustre
-soils paper and fingers
-Grey-Black
-1 hardness
-1 cleavage plane but not always visble
-Black (greenish/brownish) or grey streak
-PbS

Gypsum

-3 cleavage planes (1-perfect with 2-poor/good at 90 degrees)
-Tabular/massive or fibrous
-Vitreous to silky lustre
-White or Colourless
-Hardness of 2
CaSO4*2H2O

Halite

- 3 cleavage planes (perfect at 90 degrees)
- Soluble in water
-Vitreous and sometime dull lustre
Colourless or white
-Hardness of 2-2.5

Magnetite

-Back streak
-Dark grey-Black in Colour
-No cleavage
-dull lustre on non-fresh surface
-Attracted to a magnet
-Fe2O4
-Hardness of 6

Muscovite

-1 perfect mica cleavage direction
-Colourless to light brown
-thin flexible sheets
-Transparent
-Vitreous lustre
-Hardness of 2-3
-light streak

Olivine

-No cleavage
-Hardness of 6.5-7.5
-Olive green to yellow-green
-Vitreous to dull lustre
-commonly occurs as aggregates of small grains
-Transparent to translucent
-White Streak

Plagioclase Feldspar

- 2 cleavage planes of 90 degrees
- lamellar twinning
-vitreous lustre
-Gray-blue-gray
-White streak
-Hardness of 6

Potassium Feldspar

- 2 good cleavage planes at 90 degrees
-light and dark banding
-simple twinning
-vitreous lustre
-hardness of 6
-salmon-pink, white, gray, green
-Hardness of 6

Pyrite

-Greenish-Black Streak
-Hardness of 6-6.5
- brass-yellow colour
-Cubic Habit or massive
-FeS2

Pyroxene

2 cleavage directions
-light streak
-Dark green to black
- short prismatic 8-sided crystals
-Vitreous to dull lustre
-2 imperfect cleavages at 90 degrees
-Hardness of 6
-single chain silicate

Quartz

-No cleavage planes
-Hardness of 7
-Colourless, Milky, White, Purple, Smoky, Gray, Pink
-Conchodial Fracture
- transparent to translucent
-vitreous lustre
-6-sided crystals

Sphalerite

-Yellow Streak
-brown to yellow or black colour
-6 perfect dodecahedral cleavage
-Resinous lustre

Sylvite

- 3 cleavage directions at 90 degrees
- Hardness of 2.5
-Orange/salmon; reddish; colourless, white, grey
-Soluble in water
-Bitter taste
-Vitreous to dull lustre

Mohs hardness of 10

Diamond

Mohs hardness of 9

Corundum

Mohs hardness of 8

Topaz

Mohs hardness of 7

Quartz

Mohs hardness of 6

Orthoclase

Mohs hardness of 5

Apatite

Mohs hardness of 4

Fluorite

Mohs hardness of 3

Calcite

Mohs hardness of 2

Gypsum

Mohs hardness of 1

Talc

Silica Oxygen Tetrahedral

Anion is the silica tetrahedra

Single Tetrahedral Silicates

Olivine, Forsterite, Fayalite, Zircon, Garnet

Single Chain Silicates

Augite

Double Chain Silicates

Hornblende

Sheet Silicates

Biotite and Muscovite

Three-Dimensional framework Silicates

Potassium Feldspar and Quartz

Neosilicates

Isolated silica tetrahedral

Inosiliates

Chain of silica tetrahedral

Phyllosilicates

Sheets of silica tetrahedra

Tectosilicates

3D framework of tetrahedra

Trends in magnetism (silicates)

The smaller the silicate structure the more magnetic and the larger the structure the less magnetic

Trends in Mafic behaviour

Smaller the silicate tetrahedra the more mafic

Clay Group

Sheet silica minerals with water trapped between the sheets

Kaolinite

Forms china clay

Serpentine

Formed by metamorphism of basalt

Quartz Group

Continuously bonded silica tetrahedra

Feldspar Group

Interlocked Tetrahedra of SiO4 and AlO4 and metal cations

Zeolites

Interlocking SiO4 and AlO4

Carbonate Group

Has a Carbonate Radical (CO3)^2

Sulphate group

SO4

Native elements

Comprised of a single element

Sulphides

Minerals with sulfide
Sphalerite Chalcopyrite, Pyrite, Galena

Oxides

Minerals containing oxygen

Haemetite

-not spontaneously magnetized
-major source of iron ore

Alumina, Corundum

-Impurities determine color
-oxide
- hard mineral

Uraninite

-Radioactive mineral
-UO2, U3O8