All About the Properties and Locations of Garnets

GARNET.

Almandine, almandite, Syrian garnet, essonite, cinnamon-stone, pyrope, Bohemian garnet, vermeille, Cape garnet, Cape ruby, Arizona ruby, American ruby, carbuncle, uwarowite, demantoide, grossularite, and Bobrowska garnet are some of the scientific and commercial names for different species and colors of the garnet group.

The crystallization of the garnet is isometric, refraction single, specific gravity 3.15 to 4.3, hardness 5 to 8, lustre vitreous, fracture uneven, colors red, violet, brown, yellow, green, and white, and the various shadings of these colors.

Most varieties fuse easily to a brown or black glass; the uwarowite fuses with borax to a clear chrome-green glass.

Syrian, almandine, almandite, and carbuncle are different names for the ironalumina garnet.

In colors, these stones shade from deep-red to violet and brownish-red, and are composed of:

Silica 36.01

Alumina 20.06

Protoxide of iron 43.03

The specific gravity is 4. to 4.2, and hardness 7.5.

This garnet, sometimes called the precious garnet, is found in Ceylon, Pegu, Brazil, Greenland, Hindustan, Bohemia, Tyrol, CEtzthal, Carinthia, Styria, Switzerland, Ariolo, Canaria, Maggia, Hungary, Sweden, Norway, Scotland, Spain, and the United States.

Grossularite, or lime-alumina garnet, is known in commerce as essonite, or cinnamon-stone. The color is yellow, of various shades; specific gravity 3.5 to 3.65, and hardness 6.5.

These stones are sometimes sold for jacinths, but they are softer than the jacinth, and melt easily before the blowpipe. Essonites come principally from Ceylon, but are also found in other places.

Pyrope or Bohemian garnet is the magnesia-alumina variety, and is of a uniform dark blood-red color. This stone is found in Bohemia, and although quantities of small pieces are found, large specimens are rare, and a piece that will cut into a four- or five-carat stone is seldom met with and commands a high price.

These garnets are found at Stiefelburg by Meronitz, Triblitz, Podsedlitz, and Neupaka.

The pyrope turns black under the blow-pipe, then red again, and melts with difficulty into a black glass. With borax it melts to an emerald-green glass. The specific gravity of this garnet is 3.69 to 3.78, and hardness 7.5.

Vermeille is a name given to the orange-red almandine, Cape garnet to the bright red-yellow variety, Cape ruby to the pyrope, and American ruby to the blood-red kind found in New Mexico, Montana, and Arizona. Carbuncle is a term applied to all garnets cut with a smooth rounding top, sometimes called, after the French, cabochon.

Uwarowite or lime-chrome garnet is one of the rarest and most beautiful of the garnet group.

The color of this stone is emerald-green, hardness 7.5, and specific gravity 3.41 to 3.52. Uwarowites are found near Bissersk in the Urals of Russia, but rarely in specimens of sufficient size to cut into gems.

This garnet is heavier and harder than the true emerald.

Demantoide or Bobrowska garnet is a soft garnet, olive-green to brown and blackish-green in color, sometimes light green. It is found in the Bobrowska River in the Urals. The specific gravity is 3.85, and hardness about 6, its softness making it undesirable for many ornaments. Before the blow-pipe it fuses into a black bead.

These garnets are often sold as olivines; they are heavier than olivines and softer.

Demantoide is composed of:

Silica 35.44

Lime 32.85

Sesquioxide of iron 32.85