Kyanite

Chemical Formula

Al2SiO5

Chemical Class

Silicates

Properties

This sample was found in Coronel Murta (MG).

Origin

This sample was found in Coronel Murta (MG).

Curiosities

Did you know that, even though the kyanite name means ‘blue’, it can also be black, green, colorless or brown? Another curious fact is that kyanite has exactly the same composition as two other minerals: andalusite and silimanite. The difference among them is that each one has its own crystalline structure.

Use

Kyanite is used mainly as refractory mineral, due to its great and irreversible thermal expansion, that enables neutralizing the normal contraction present in most of the other refractory materials, as clays. Approximately 95% of the kyanite production in the world is consumed by refractory industries, out of which 60% are designed to ferrous metal casting and processing, 20% to non-ferrous metals and 15% to glass and ceramic manufacturing. Kyanite photo credit: Henry Yu

ABC of mining