small
quantities of gold and cobalt. It occurs in crystals, in compact ard
granular masses, is silver-white in color, and closely resembles
cobalt. It is abundant in Saxony, Sweden, Bolivia; and also in New
Hampshire, Maine and Connecticut.
It is used in the manufacture of insecticides and pigments, etc.
Asbestos: A
fibrous variety of several members of the Hornblende family.
Actinolite, Tremolite, Chrysotile, etc., composed of separate filaments
of a silky luster. It is incombustible and is used as fire-proofing
material, for gas-logs in grates, firemen's clothing, etc., also for
insulating and packing steam joints. The name, Asbestos, is from the
Greek, meaning unquenchable.
Atacamite: Copper
14.9%, Chloride 16.6%, Cupric Oxide, 55.8% Water 12.7%. A comparatively
rare copper mineral, found usually in crystalline, fibrous or granular
masses of a bright green color. This mineral changes on exposure to the
weather, to the carbonate, Malachite, and the silicate, Chrysocolla. It
was originally found at Atacama, Chile, from which place it takes its
name. In the United States it occurs in California and Arizona.
Autunite: Hydrous
Phosphate of Uranium and Calcium. Uranium Tri-oxide 62.7%. It occurs
in thin tabular crystals and in foliated and micaceous masses; is lemon
yellow or sulphur-yellow in color, and closely resembles Torbernite.
It is recognized by its color, streak and specific gravity, and occurs in
veins and on the walls of cracks in rocks, especially in association
with other uranium ores of which it is a decomposition product.
It occurs in Russia, Saxony; Autin, England; and also in South
Dakota, Utah and Colorado. (See Radium).
Aurichalcite: A
basic carbonate of Zinc and Copper. Zinc Oxide 53%, Cupric Oxide
20.8%. It occurs in acicu-lar crystals forming drusy incrustations;
also columnar and granular. Color pale green and sometimes sky-blue.
It is found in Hungary, Derbyshire, Leadhills; also in the Big
Cottonwood Mines in Utah, and in Arizona.
Aventurine: Quartz containing brilliant scales of Hematite and Mica. It is used for settings in jewelry, and for small ornaments such as paper-weights and umbrella handles, (see Albite).
Axinite: Anhydrous
Orthosilicate. A boro-silicate of Aluminium and Calcium, with varying
amounts of Iron and Manganese. This mineral is especially noteworthy
for its
richness in crystal forms, these crystals being strongly pyro-electric.
