Photo of Andradite in Processed & Rough Form
Andradite is a mineral with a hardness of 7 out of 10 on the Mohs scale of mineral hardness [?]. These Cubicly structured gems are made of calcium iron silicate, their full chemical compound being Ca3Fe2(SiO4)3.
Andradite is a name given to members of the garnet that contain manganese and titanium. The 3 types Andradite are..1.)Demantoid, 2.)Melanite, and 3.) Topazolite
Demantoid-the word means diamond like. It is yellow green to green in color and is the most valuable of the 3 types. Demantoid is soft enough that older gems will have facet edges that are slightly worn. Largest deposits have been found in the United States, China, and Russia.
Melanite-also called Black Melanite is black (duh), looks like black glass, and like Demantoid, Melanite is soft enough that older gems will have facet edges that are slightly worn.
Topazolite-Like Demantoid and Melanite Topazolite is soft enough that older gems will have facet edges that are slightly worn. Topazolite gets it's name from its similarity to Topaz.
Andradite has the ability to separate light into more colors than even the mighty diamond. If you are hunting for this gem check near metamorphosed limestone deposits.
The specific gravity [?] for Andradite is 3.85, its refractive index [?] is 1.85-1.89, and its double refraction [?] is None.
History
Andradite is named after mineralogist Jose Bonifacio de Andrade, and it was first recorded in 1868 in Norway.
Industrial Usages
Garnets in general are good abrasives for sand blasting, and cutting of steel via pressurized water jets. Fine powdered versions of garnet can be found along shorelines in large quantities.
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