Field book of common rocks and minerals : $b for identifying the rocks and minerals of the United States and interpreting their origins and meaningsLoomis, Frederic Brewster
Science
Field book of common rocks and minerals : $b for identifying the rocks and minerals of the United States and interpreting their origins and meanings
Loomis, Frederic Brewster
Minerals -- United States; Rocks -- United States
Pyrope is a deep-red color and when perfect is highly prized as a gem.
It is found in dark-colored igneous rocks, like lavas, or serpentines.
Some of the finest come from South Africa, where they are found in
company with the diamond.
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
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