Chondrodite: Fluo-silicate
of Magnesium. A brittle mineral occurring disseminated through primary
limestone. Its color is light yellow, dark yellow and honey-yellow,
and sometimes dark red- brownish red and hyacinth red. It is found as
crystals in the blocks enclosed in the lavas of Vesuvius, in the copper
mines of Sweden, and in limestone in Finland. In Brewster, N. Y., and
Orange Co., N. Y. (see Brucite).
Chromite: This
mineral is the principal ore of Chromium. Chromium 68%, Iron protoxide
32%. It occurs in crystals, aggregates and masses, and in a few places
as sand on beaches. In the United States it occurs in a belt of
Serpentine in the Rocky Mts., the Sierra Nevadas and the Coast Ranges.
Chromium is employed in the manufacture of special grades of steel. The
salts are used in tanning, and as pigments. The crude ore is molded
into bricks and used as linings in metallurgical furnaces. It is also
used as an oxidizing agent, and in batteries and photography.
Chrysoberyl: Beryllium
Aluminate. Chrysoberyl is characterized by its great hardness and
crystallization. It most resembles the beryllium silicate, Beryl, in
appearance but is easily distinguished from this by its
crystallization. It is found principally in granites and crystalline
schists and as grains in the sands produced by the erosion of these
rocks. It is a comparatively unknown gem of great beauty, is nearly as
hard as sapphire, and distinctly pleochroic, appearing light green or
yellow by reflected light and distinctly red by transmitted light. The
variety. Alexandrite, is a gem of beauty. Its best known localities are
Minas Geraes, Brazil; Ekaterinberg, Ural; in Ireland; at Haddam,
Connecticut; and at Stoneham, Maine. The Alexandrite comes from Ceylon,
where it occurs as pebbles.
Chrysocolla: A
minor ore of Copper. Copper 45.2%, 34.3% of Silica. The true
composition is still doubtful. It has an opal-like or earthy
translucent structure, is green or lurquoise-blue, and the impure
varieties brown, or even black. It is sometimes called "False
Turquoise." Chrysocolla is mined with other ores of copper and is
treated with them for the metal it contains. Polished matrix pieces are
very attractive and are being much used in art jewelry. It occurs in
all copper mines, especially in Bohemia, Italy, Russia and Chile; as
blue crusts on the basalts at Somerville, N. J.; as a bluish-green
matrix at the Old Dominion Mine, Globe, Arizona; and intergrown with
Opal at Boleo Mine, California.
Chrysolite: A
mineral composed of silica, magnesium and iron. The prevailing color is
some shade of green. Although principally important as a rock
constituent, this silicate
when transparent is often cut for a semi- precious stone. These
