Almandine is a mineral with a hardness of 8 out of 10 on the Mohs scale of mineral hardness [?]. These Cubicly structured gems are made of iron aluminum silicate, their full chemical compound being Fe3Al2(SiO4)3.
Almandine or Almandite is a member of the Garnet group, and is associated with the planet Pluto. Low quality pyrope is often cataloged and sold as Almandine. Almandine is generally darker than pyrope.
Almandine colors vary from red to dark red, purple to purplish red, and even pink.
Almandine is valued fairly low at somewhere between $5 and $225 a carat all dependent upon clarity, color, cut, and lack of inclusions.
Despite its lack of popularity Almandine in great condition and cut correctly is a very beautiful stone.
The specific gravity [?] for Almandine is 4, it's refractive index [?] is 1.76-1.83, and it's double refraction [?] is None.
History
Almandine was very popular in the 19th century.
Noah (from the Hebrew Bible) used Garnet to light the Ark. It is also used in stained glass windows of churches around the world.
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.