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Bauxite
Bauxite - Mineral Properties and Uses |
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What is Bauxite? |
Bauxite is a rock composed mainly of aluminum oxide and aluminum hydroxide minerals. These might include: gibbsite, boehmite and diaspore. The rock usually includes other materials such as iron hydroxides, clay, silt and free silica. It most often occurs as a residual soil material in tropical and subtropical areas. It is the primary source of aluminum. |
Uses |
Bauxite is the most common ore of aluminum. It is also used as an abrasive, however, this use is now being replaced by synthetic materials. |
Color |
white, gray, yellow, red |
Streak |
normally white but may streak other colors if the specimen is stained |
Luster |
dull to earthy |
Diaphaneity |
translucent |
Cleavage |
because bauxite is a mixture of gibbsite, boehmite and diaspore, it has no cleavage properties of its own |
Hardness |
1 to 3 |
Specific Gravity |
2 - 2.5 |
Distinguishing
Characteristics |
pisolitic structure, color |
Crystal System |
Bauxite is a mixture of Diaspore (orthorhomic), Gibbsite (monoclinic), and Boehmite (orthorhombic) |
Chemical Classification |
oxide / hydroxide |
Chemical Composition |
gibbsite, Al(OH)3
boehmite, AlO(OH)
diaspore, AlO(OH) |
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Bauxite from Little Rock, Arkansas.
Specimen is approximately 4 inches (10 centimeters) across.
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Pisolitic structure of bauxite mineral from Little Rock, Arkansas.
A detailed view of the specimen shown above..
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Bauxite from Demerara, Guyana.
Specimen is approximately 4 inches (10 centimeters) across.
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Bauxite from Little Rock, Arkansas.
Specimen is approximately 4 inches (10 centimeters) across.
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