Franklinite: An
Oxide of Iron, Zinc and Manganese. Found in zinc deposits at Franklin,
New Jersey, from which it takes its name. This is an important ore
mineral and resembles Magnetite in general appearance, fracture and
cleavage, but it is only slightly magnetic. It occurs in crystals,
granular and structureless; is black and lustrous. It is found in only
a few places, the most noted are Franklin Furnace and Sterling Hill, N.
J. It is used in the manufacture of certain grades of steel.
Gadolinite: Orthosilicate.
A rather rare mineral with a composition that is not well established.
It is found massive and in rough crystals, and is usually black or
greenish.
It occurs in pegmatites near Stockholm, Sweden and is also found in
Norway; in Harz; in Texas and Colorado.
Gahnite: Zinc
Aluminate. Alumina 56%, Zinc 44%. Common variety of Spinel, with
colors of dark green, grayish-green, leek-green, greenish-black,
bluish-black, yellow
or brown.
Galena: Lead
Sulphide. Lead 87%, Sulphur 13%. Sometimes contains a little gold and
silver. This is the most important ore of Lead and occurs in great
lead-gray crystalline masses; in large and small crystals; and in fine
and coarse granular aggregates. This mineral is very widely spread. The
most extensive Galena deposits in this country are in Missouri, and in
the corner made by the states of Wisconsin, Illinois and Iowa. The
metal, lead, finds many uses in the arts, but is most commonly used for
piping.
The most modern use of Galena is for Radio transmission.
Garnet: An
Orthosilicate. A semi-precious stone, rich in color. Although the
typical garnet color is well known, the ruby-red, violet-red,
brownish-yellow, orange, green or purple-red stones are comparatively
unfamiliar. Some of the different varieties are as follows:
Grossularite or Essonite, or "Cinnamon Stone," yellow.
Pyrope, deep red, sometimes nearly black.
Almandite, red, brownish-red or black.
Spessartite, reddish-brown or violet-brown.
Andradite, black, brown or yellowish.
Ouvarovite or Uvarovite, emerald green.
The
finest purple-red stones come from Bohemia, where they have, from very
ancient times, been considered a sort of national jewel. The Garnet
ranks among the less expensive semi-precious stones, and though
beautiful in color, is lacking in "fire." It is used as settings
