Kyanite

Kyanite is a silicate with composition Al₂SiO₅ . This sample is about 18x18 cm and is from Monte Campione, Uri, Switzerland. The chemical compostion is the same as the minerals sillimanite and andalusite. These samples are on display at the Smithsonian Museum of Natural History.

The slender crystals are about 0.5x10 cm. These samples are from Minas Gerais, Brazil.