Wednesday, March 24, 2010

Andalusite Facts

Andalusite is a mineral with a chemical formula of Al2SiO5. Andalusite often occurs in metamorphic rocks, such as schists, hornfels and granite. It is sometimes used as a gemstone.


Color


Andalusite often appears brown, green, reddish brown, pink, yellow, white, gray or violet. The color depends on the chemicals in the rock. Since andalusite is pleochroic, its color changes when you look at it from different angles.


Features


Andalusite has a hardness ranging from 6.5 to 7.5. Its specific gravity measures between 3.13 and 3.17. Andalusite has an orthorhombic crystal system, which means that its crystals have rectangular prisms and rectangular bases.








Location


Andalusite has been found in Spain, Austria, Germany, Ireland, Brazil, Sri Lanka and Australia. In the United States, deposits exist in Massachusetts, California, Pennsylvania and South Dakota.


Fun Fact


Andalusite was named after Andalusia, Spain, a location that has large deposits of the rock.

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