Almandite is dark-red to brown in color, the brownish-cast distinguishing it from pyrope. It is one of the garnets known as “common garnet.” In some cases it is clear and deep colored enough to be used as a gem, but mostly it is muddy in appearance. The name almandite comes from Alabanda, a city of the ancient district of Caria, Asia Minor, whence garnets were traded to ancient Rome. The finest garnets “Sirian garnets” came from the city of “Sirian” in Lower Burma, and were supposed to have been found near there, but careful investigation shows that no garnets occurred near there, and this town was therefore, even at that early time, a distributing point for garnets, found probably further to the east. The “Sirian” garnet had a violet cast and now the term is used to indicate a type of garnet, rather than a locality.
Spessartite is dark-hyacinth-red, or red with a violet-tinge, and is one of the less-common garnets. It is usually found in granites. The finest garnets of the type come from Amelia Court House, Va., which has yielded some ranging from one up to a hundred carats.
Andradite is another garnet which is termed “common garnet.” It is red in color, but with a yellowish-cast which distinguishes it from almandite, but these two are not easy to separate. It is found mostly in metamorphosed limestones. One variety is black in color and called malanite. It is found in lavas. The common yellowish-red garnets are found through New England and the Piedmont Plateau.
Uvarovite is a rare garnet of emerald-green color, found in association with chromium ores.
The number of localities for garnets is so great that a list would suggest most of the regions where metamorphic rocks occur, as all over New England, throughout the Piedmont Plateau, the Rocky Mountains, etc. Certain fine clear garnets, found in Montana, northeastern Arizona, and northwestern New Mexico are sold under the trade name of “Montana, Arizona or New Mexico rubies.” These are of fine quality and are mostly collected by the Indians from the ant hills and scorpion’s nests of those regions.
Garnets are among the earliest stones mentioned in ancient languages, as would be expected from the way these hard and beautiful crystals weather out of the much softer metamorphic rocks, like schists. In the past they, with most any other translucent red stone, were included under the name carbuncle. This, however, is not the name of any mineral, but refers rather to a mode of cutting, en cabochon or with a convex surface.
Glucinum
Glucinum is a rare metal, silvery-white in color, malleable, and melting at a fairly low temperature. It is found in the mineral beryl, from which has come the alternative name beryllium. The name comes from the sweet taste of its salts. Except for beryl its minerals are rare, and the metal has found but few uses for man.
[Beryl]
Gl₃Al₂(SiO₃)₆
[Pl. 39]
Occurs in hexagonal crystals in granites, gneisses and mica schists; hardness, 7.5; specific gravity, 2.7; color usually some tint of green; luster vitreous; transparent on thin edges.