Andalusite

The name, Andalusite, is an homage to the city of Andalusia, Spain. Gem quality examples of this mineral species are somewhat rare. Running the gamut from transparent to opaque, these highly pleochroic gems are usually in the brown to green range with some rare pink or violet-hued examples. The most easily identifiable variety is chiastolite because of its unusual cross-like inclusion. Historically, chiastolite had appeal as an amulet because of its distinctive pattern which currently makes it popular with collectors.

Andalusite var. Chiastolite.

Gemological Information for Andalusite

  
Color:Brownish to Yellowish Green, Green, Brown, rarely Pink
Crystal Structure:Orthorhombic
Refractive Index:1.6345 – 1.643
Durability:Fair to Good
Hardness:7 to 7.5
Family:Chiastolite – Features a Cross Pattern
Similar Stones:Tourmaline, Topaz, Barite, Apatite, Danburite, Chrysoberyl
Treatments:Heat Treatment
Country of Origin:Brazil, Sri Lanka

Andalusite Care

  
Ultrasonic Cleaning:Use Caution
Steam Cleaning:Risky
Warm Soapy Water:Safe
Chemical Attack:None
Light Sensitivity:Stable
Heat Sensitivity:Check for Liquid Inclusions

Gems & Gemology: The Quarterly Journal of the Gemological Institute of America

Andalusite:

  • Winter 1948, An 85 ct. Rough Andalusite Believed to be One of the Finest, p. 124, 2pp.
  • Winter 1960, A 32 ct. and a 20 ct. Flawless Cut Andalusite (Showing Absorption Spectrum), p. 121, 1p.
  • Summer 1961, The Andalusite Absorption Spectrum, p. 185, 2pp.
  • Fall 1976, Inclusions in Brazilian Andalusite, p. 201, 2pp.
  • Winter 1980, Inclusions in Andalusite – A Comparison of Localities, by John I. Koivula, p. 401, 4pp.