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The Mineral boehmite

Boehmite and Natrolite

Boehmite, also spelled as Böhmite, is one of the three component minerals of the economically important aluminum ore Bauxite. It is named after German mineralogist Johann Böhm.

Chemical Formula

AlO(OH)

Color

White, light gray, light yellow, light yellow-green

Crystal System

Orthorhombic

Properties

Streak
White

Hardness
3 - 3.5

Transparency
Translucent

Specific Gravity
3 - 3.1

Luster
Vitreous

Cleavage
1,1;2,1;3,1

Fracture
Uneven

Tenacity
Brittle

Crystal Habits

Crystals, which are tabular or short prismatic, form in tight groups and are very small. Most often in fine-grained scaly masses, pisolitic, and massive.

Additional Information

Composition
Basic aluminum oxide

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 and pegmatites.

Rock Type
Igneous, Sedimentary

Other Names

Bohmite

Synonym of Boehmite. Usually spelled in the native German Böhmite.

Uses

Boemite, being an important component of Bauxite, is an important ore of aluminum.

Noteworthy Localities

Although common as a constitute in Bauxite deposits, Boehmite is very poorly represented as specimens. The locality of Saga 1 Quarry, Mørje, Telemark, Norway has produced good microcrystals of Boehmite.