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A pitch-black mineral consisting chiefly of the oxide of uranium; uraninite. See Uraninite.

The work of a coal miner who is paid by a share of his product.

A deposit of earth, sand, or gravel, containing valuable mineral in particles, especially by the side of a river, or in the bed of a mountain torrent. [U.S.]

A cavity in a rock containing a nugget of gold, or other mineral; a small body of ore contained in such a cavity.

, to direct the attention or notice of. Whosoever should be guided through his battles by Minerva, and pointed to every scene of them. Pope.

A colorless transparent mineral, resembling quartz, occurring with castor or castorite on the island of Elba. It is a silicate of alumina and cæsia. Called also pollux.

A mineral usually occurring in fibrous masses, of a brick-red color, being tinged with iron, and consisting chiefly of the sulphates of lime, magnesia, and soda.

ndantly but always combined, as in the chloride, sulphate, carbonate, or silicate, in the minerals sylvite, kainite, orthoclase, muscovite, etc. Atomic weight 39.0. Symbol K (Kalium).

species of ore which, from its aptness to vitrify like the glazing of potter's wares, the miners call by this name. Boyle.

A pale green mineral occurring in crystalline aggregates having a botryoidal or mammillary structure, and rarely in distinct crystals. It is a hydrous silicate of alumina and lime.

An examiner; an approver. Maydman.

One who prospects; especially, one who explores a region for minerals and precious metals.

A kind of granite or gneiss containing a silvery talcose mineral.

Falsely or imperfectly metallic; -- said of a kind of luster, as in minerals.

A common mineral of a pale brass-yellow color and brilliant metallic luster, crystallizing in the isometric system; iron pyrites; iron disulphide. Hence sable coal his massy couch extends, And stars of gold the sparkling pyrite blends. E. Darwin.

A name given to a number of metallic minerals, sulphides of iron, copper, cobalt, nickel, and tin, of a white or yellowish color.

or pertaining to characters developed by the use of heat; pertaining to the characters of minerals when examined before the blowpipe; as, the pyrognostic characters of galena.

The characters of a mineral observed by the use of the blowpipe, as the degree of fusibility, flame coloration, etc.

Manganese dioxide, a mineral of an iron-black or dark steel- gray color and metallic luster, usually soft. Pyrolusite parts with its oxygen at a red heat, and is extensively used in discharging the brown and green tints of glass (whence its name).

A mineral which is opaque in its natural state, but is said to change its color and become transparent by heat.