for
all kinds of jewelry. The common variety is used as an abrasive in
place of emery, and in making the better grades of sandpaper. In the
United States garnets are found in Maine, North Carolina, Virginia,
Colorado and California.
Garnierite: A
new mineral from Noumea, New Caledonia. This is an important ore of
nickel but variable as to composition. It may be regarded as a
serpentine or talc, in which a portion of the magnesium has been
replaced by nickel. There are two varieties, one dark green and
unctuous (Noumeite), and the other pale green and adhesive to the
tongue. Its importance consists in the fact that it is the only
commercial source of nickel, aside from the Pentlandite in the
Pyrrhotite, of Sudbury, Canada.
Genthite: Silicate.
Silica 34.8%, Nickel 28.8%, Magnesia 15.5%. A gymmite with part of the
magnesium replaced by nickel. It occurs in amorphous masses and
reniform incrustations, apple-green and emerald-green in color, of
little luster and translucent.
Gibbsite: Aluminium
Hydrate. Alumina 65%. Named after Col. George Gibbs, original owner of
the Gibbs Cabinet at Yale University. This mineral occurs as crystals,
in granular masses, as stalactites, in fibrous radiating aggregates,
and is used to some extent as an ore of Aluminum. It is transparent or
translucent; in color white, pink, green or gray, and is a
non-conductor of electricity.
Gilpinite: A new mineral associated with Uraninite, an ore of Radium, in Gilpin County, Colorado.
Gmelinite:
Silica 47%, Alumina 20%, Soda 12%. Occurs in flesh-red crystals in
Europe, and in fine white crystals at Bergen Hill, N. J. It occurs also
yellowish-white,
greenish-white and reddish-white. Weak double refraction.
Goethite: Hydrous
Oxide of Iron. Iron 63%, Oxygen 27%. This mineral is named after the
Poet-Philosopher, Goethe. Though occasionally found in brown crystals, it usually
occurs in radiated globular, and botryoidal masses. Its color is
usually yellowish, reddish or blackish-brown. In thin splinters it is
often translucent with a blood-red color. It is an electric
non-conductor. This mineral is found in fine large crystals in
Cornwall, England. In the United States it occurs in small quantities
in Michigan, Connecticut, Pennsylvania, and a few other places. It is
used as an ore of iron. A reddish variety found in Harhausen, Germany,
is called "ruby glimmer."
