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A common mineral embracing many varieties varying in color and in composition. It occurs in monoclinic crystals; also massive, generally with fibrous or columnar structure. The color varies from white to gray, green, brown, and black. It is a silicate of magnesium and calcium, with usually aluminium and iron. Some comm…

Of or resembling the mineral amphibole.

containing small cavities, occupied, wholly or in part, by nodules or geodes of different minerals, esp. agates, quartz, calcite, and the zeolites. When the imbedded minerals are detached or removed by decomposition, it is porous, like lava.

A white or flesh-red mineral, of the zeolite, occurring in isometric crystals. By friction, it acquires a weak electricity; hence its name.

A mineral of a white a slightly bluish color, usually massive. It is anhydrous sulphate of lime, and differs from gypsum in not containing water (whence the name).

A mineral closely related to dolomite, but containing iron.

A mineral of the feldspar family, commonly occurring in small glassy crystals, also a constituent of some igneous rocks. It is a lime feldspar. See Feldspar.

A mineral of the hornblende group, of a yellowish gray or clove brown color. -- An`tho*phyl*lit"ic, a.

A hard, compact variety of mineral coal, of high luster, differing from bituminous coal in containing little or no bitumen, in consequence of which it burns with a nearly non luminous flame. The purer specimens consist almost wholly of carbon. Also called glance coal and blind coal.

An effervescing alkaline mineral water used as a table beverage. It is obtained from a spring in Apollinarisburg, near Bonn.

A mineral relating to the zeolites, usually occurring in square prisms or octahedrons with pearly luster on the cleavage surface. It is a hydrous silicate of calcium and potassium.

A mineral identical in composition with calcite or carbonate of lime, but differing from it in its crystalline form and some of its physical characters.

The state of being arborescent; the resemblance to a tree in minerals, or crystallizations, or groups of crystals in that form; as, the arborescence produced by precipitating silver.

The appearance or figure of a tree or plant, as in minerals or fossils; a dendrite.

A mineral of a tin-white color and metallic luster, containing arsenic, sulphur, and iron; -- also called arsenical pyrites and mispickel.

man skill and labor, in opposition to natural; as, artificial heat or light, gems, salts, minerals, fountains, flowers. Artificial strife Lives in these touches, livelier than life. Shak.

The earthy or mineral particles of combustible substances remaining after combustion, as of wood or coal.

Mineral pitch, Jews' pitch, or compact native bitumen. It is brittle, of a black or brown color and high luster on a surface of fracture; it melts and burns when heated, leaving no residue. It occurs on the surface and shores of the Dead Sea, which is therefore called Asphaltites, or the Asphaltic Lake. It is found als…

A mineral occurring in triclinic crystals approaching pyroxene in angle, and of a greenish black color. It is a silicate of iron, manganese, and lime.

Native sulphate of barium, a mineral occurring in transparent, colorless, white to yellow crystals (generally tabular), also in granular form, and in compact massive forms resembling marble. It has a high specific gravity, and hence is often called heavy spar. It is a common mineral in metallic veins.…