Overview

Aluminum oxide (uh-LOO-min-um OK-side) is white crystalline powder that occurs in nature in a variety of minerals, including boehmite, bayerite, corundum, diaspore, and gibbsite. Corundum is second hardest naturally occurring mineral. Only diamond is harder. Aluminum oxide occurs in a variety of chemical forms in a variety of gemstones, including chrysoberyl, ruby, sapphire, and spinel. The color of these gemstones is a result of impurities, such as chromium (in the case of ruby) and iron and titanium (in the case of sapphire). The colors may also vary depending on the kind and amount of each impurity.

Aluminum oxide's commercial uses depend not only on its hardness, but also on its high melting point and its low electrical conductivity. The compound is also non-combustible and resistant to attack by most solvents and other chemical agents.

Key Facts

Other Names:

Alumina

Formula:

Al₂O₃

Elements:

Aluminum, oxygen...