mineralogy some common minerals illustrated by charina cameron
DESCRIPTION
Major Properties of Minerals Crystal form Luster (metallic, non-metallic, etc.) Colour (often due to impurities) Streak (colour of powder) Hardness (Moh’s scale: 1 to 10) Cleavage –none or up to 6 surfaces –planes of weakness in crystal structure Fracture (conchoidal, etc.) Specific gravity –density compared to water –galena is much greater than quartz (2.65)TRANSCRIPT
MINERALOGYSome Common Minerals
Illustratedby Charina Cameron
Mineral Groups• Nearly 4000 minerals• Only a few dozen are abundant in Earth’s crust• These are the rock-forming minerals• 8 elements comprise the bulk of these minerals• They also represent 98% of the continental crust:
– O 47%– Si 28%– Al 8%– Fe 5%– Ca 4%– Na 3%– K 3%– Mg 2%
Silicate minerals
Major Properties of Minerals• Crystal form• Luster (metallic, non-metallic, etc.)• Colour (often due to impurities)• Streak (colour of powder)• Hardness (Moh’s scale: 1 to 10)• Cleavage
– none or up to 6 surfaces– planes of weakness in crystal structure
• Fracture (conchoidal, etc.)• Specific gravity
– density compared to water– galena is much greater than quartz (2.65)
Special Mineral Properties• Magnetic• Elastic• malleable• taste• smell• feel
– Soapy– Greasy
• Double refraction• Reaction to HCl
Moh’s HARDNESS SCALE
Talc
Gypsum
Calcite
Fluorite
Apatite
Orthoclase
Quartz
Topaz
Corundum
Diamond
1
2
3
4
5
6
7
8
9
10
Common Mineral Groups• Sulfides S2-
• Oxides O2-
• Carbonates (CO3)2-
• Sulphates (SO4)2-
• Phosphates (PO4)3-
• Halides F,Cl, etc.• Native elements Au, Cu, C, etc.• Silicates (SiO4)4-
SULFIDES
• Pyrite Chalcopyrite Galena• FeS2 (Cu,Fe)S2 PbS
• Sphalerite• (Zn,Fe)S
OXIDES
• Hematite Limonite Magnetite– Fe2O3 Fe2O3 nH2O Fe3O4
• Corundum– Al2O3
CARBONATES• Double refraction in Calcite
CaCO3
• Dolomite crystals (Ca,Mg)CO3
• Siderite• FeCO3
CARBONATES• Calcite crystals from a vein in Wolfville Formation,
showing 3 perfect cleavages not at right angles
CARBONATES• Hexagonal Calcite crystals from Scots Bay Fm
SULPHATES• Gypsum
CaSO4nH2O
• Anhydrite CaSO4
PHOSPHATES• Apatite
Ca3(PO4)2
HALIDES• Fluorite
CaF2
4 cleavages
• HaliteNaCl3 cleavages
at right angles
NATIVE ELEMENTS• Sulphur S8
• Gold Autiny nuggets panned at Ovens, Nova Scotia
• Graphite C
• Diamond C