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Gemstones 250x250

Bauxite

Bauxite From Arkansas

Bauxite is not a mineral, but rather a group of aluminum oxides. The term is generally used to describe the economically important mixture of these minerals, which form a mass of the individually classified members of Gibbsite, Boehmite, and Diaspore. Bauxite does not make aesthetic or interesting specimens as far as collectors are concerned, but it holds importance as being the primary ore of the metal aluminum. Bauxite is named after the French village of Les Baux, where it was first recognized as an aluminum ore.

Chemical Formula

Al(OH)3 with possible additional Al and (OH)

Color

Beige, yellow, white, gray, brown, reddish-brown, pink

Crystal System

Amorphous

Properties

Streak
White
Hardness
1 - 3
Transparency
Opaque
Specific Gravity
2.0 - 2.6
Luster
Dull
Cleavage
None
Fracture
Earthy
Tenacity
Brittle

Crystal Habits

Most often as pisolitic and oolitic spherical masses within a matrix. Also massive, botryoidal, and in clay-like masses. Sometimes in nodules with tiny crystals lining cavities within the nodules.

Additional Information

Composition
Basic aluminum hydroxide
In Group
Oxides; Hydroxides
Striking Features
Formation habits and mode of occurence
Environment
As a secondary mineral forming in the weathered surface zones in clay deposits and limestones, as well as low-silica igneous rocks.
Rock Type
Igneous, Sedimentary

Uses

Bauxite is mined extensively for its economical value as the principle ore of aluminum.

Noteworthy Localities

Since Bauxite specimens are not well-represented in collections due to their lack of aesthetics, this guide will not list specific localities but will rather list countries that are important producers. These include Australia, China, Brazil, Jamaica, Suriname, Guyana, French Guiana, Venezuela, Vietnam, India, and Russia. In the U.S., the leading Bauxite producer is Arkansas, which even has a town called Bauxite named after its once-famous reserves. Other states with Bauxite deposits are Georgia, Alabama, Mississippi, Tennessee, and Virginia.

Common Mineral Associations

Gibbsite, Boehmite, Diaspore, Goethite

bauxite Photos



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