Characteristics of Tennessee's Mineral Resources

Minerals are identified by a variety of characteristics

Common Name
Scientific Name
Formula
Class of Mineral
Hardness
Specific Gravity
Barite Barium Sulfate
BaSO4
Sulfate
3-3.5
4.3-4.6
Chalcopyrite (copper) Copper Iron Sulfide
CuFeS2
Sulfide
3-5.4
4.1-4.3
Chert - Calcedony Silicon Dioxide
SiO2
Silicate
7
2.6-2.64
Fluorite Calcium Fluoride
CaF2
Halite
4
3.0-3.2
Galena Lead Sulfide
PbS
Sulfide
2.5
7.4-7.6
Gypsum Hydrous Calcium Sulfate
CaSO4*2H2O
Sulfate
1.5-2
2.3-2.4
Ilmenite Iron Titanium Oxide
FeTiO3
Oxide
5.6
4.5-4.7
Hematite Iron Oxide
Fe2O3
Oxide
5.6
4.9-5.3
Limonite Hydrous Iron Oxide
FeO(OH)* nH2O
Oxide
4-5.5
2.7-4.3
Magnetite Iron Oxide
Fe3O4
Oxide
5.5-6.5
4.9-5.2
Pyrite Iron Sulfide
FeS2
Sulfide
6-6.5
4.9-5.2
Phosphate
Saltpeter Potasium Nitrate
KNO3
Carbonate2
Sphalerite Zinc Sulfide
ZnS
Sulfide
3.5-4
3.9-4.1

1 Hydrous minerals have water incorporated into their crystaline structure. Why do you think that limonite hydrous iron oxide has a specific gravity so much lower than that of the other iron oxides.

2 Nitrates are classified with the carbonates because the nitrate group NO3 interacts like the carbonate group CO3, forming weak ionic bonds which create soluble minerals.

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