Fluoride of Aluminium, Calcium and Sodium. It occurs in colorless and
white, prismatic and twinned crystals It is named from the Greek,
"Frost Stone," and is found at Ivigtul, Greenland, and at St. Peter's
rare metal closely resembling platinum in color and appearance and
found alloyed with platinum and gold. It is much used for graduated
surfaces in certain instruments, also in plating silver, and in
dentistry. It occurs with platinum in Brazil, the Urals, and in St.
Sodium Mica, corresponding to Muscovite in composition. Occurs massive
consisting of minute scales, and is yellowish, grayish, greenish and
light apple-green in color. Translucent; thin scales transparent. A
compact variety called Cossaite was first identified in an antique ring
dug up in the neighborhood of Turin.
Vanadium Sulphide. Composition somewhat variable; from 19 to 24%
Vanadium Oxide and 50 to 55% Sulphur. This mineral is of recent
discovery and carries a
larger percentage of Vanadium and occurs in greater quantities than
any other vanadium mineral.
is coke-like in appearance and carbonaceous and black in color. Filed
and polished in dry weather, it gives a shining, silvery appearance,
but in damp weather it exudes an ink-like substance. Patronite is the
source of much of the world's present supply of Vanadium, which is
employed in the manufacture of certain grades of steel and bronze.
Vanadium is named after Vanadis, a Scandinavian deity.
Patronite's occurrence is limited to one locality—Cerro de Pasco, Peru.
silvery or bluish-white, hard, smooth, lustrous substance produced by
certain species of mollusks as the result of some abnormal secretion.
The production is generally begun by the introduction of some foreign
substance such as a grain of sand. This causes an irritant action
resulting in a process of covering the sand or object with gradually
increasing layers of mother-of-pearl with which the shell is lined.
This gradual process results in the beautiful gem, the Pearl Though
highly prized as a precious stone, the Pearl is not regarded as a
among the Pearl-producing mollusks, are the pearl-oysters of the Indian
Sea and the fresh water mussels of the rivers of the