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Andalusite

Chemical Formula

Al2SiO5

Chemical Class

Silicates

Properties

Andalusite is a Silimanite and Kyanite trimorph. These three minerals, with identical chemical composition, but with different crystalline arrangement, are used to manufacture spark plug porcelain, and high quality refractory manufacturing.

Origin

Chile

Curiosities

Andalusite has such name as it was discovered in Andalusia Spanish Province, in 1798. When it has carbon inclusions arrange in cross shape, it is named Chiastolite (from the Greek Chiastos = cross).

Use

Transparent and clear andalusites, have gemological use. Whenever they are facetted, they are red, green and yellow color scheme, due to the strong pleochroism (color variation according to the light incidence).

Source: MM Gerdau - Museu das Minas e do Metal -

ABC of mining

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