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A hydrous carbonate of alumina and soda, occuring in white, bladed crustals.

A hydrate of alumina, often occurring in white lamellar masses with brilliant pearly luster; -- so named on account of its decrepitating when heated before the blowpipe.

Any earthy-looking metallic oxide, as alumina, glucina, zirconia, yttria, and thoria.

A grayish white zeolitic mineral, in tetragonal crystals. It is a hydrous silicate of alumina and baryta.

A hydrous phosphate of alumina and manganese. It is generally of a rose-pink color, -- whence the name.

r, occurring granular, massive, columnar, and in monoclinic crystals. It is a silicate of alumina, lime, and oxide of iron, or manganese.

A crystallized, transparent mineral of the Zeolite family. It is a hydrous silicate of alumina and lime.

, transparent crystals, affording a brilliant clinodiagonal cleavage. It is a silicate of alumina and glucina.

e given to a group of minerals, closely related in crystalline form, and all silicates of alumina with either potash, soda, lime, or, in one case, baryta. They occur in crystals and crystalline masses, vitreous in luster, and breaking rather easily in two directions at right angles to each other, or nearly so. The colo…

A silicate of alumina, of fibrous or columnar structure. It is like andalusite in composition; -- called also sillimanite, and bucholizite.

A hydrate of alumina.

A native hydrated silicate of alumina, lime, and potash, first noticed near Rome.

never occurs naturally in the free state, but is always combined, usually with silica or alumina, or both; as in the minerals phenacite, chrysoberyl, beryl or emerald, euclase, and danalite. It was named from its oxide glucina, which was known long before the element was isolated. Symbol Gl. Atomic weight 9.1. Called…

A hydrous silicate of alumina and baryta, occurring usually in white cruciform crystals; cross-stone.

monoclinic crystals with pearly luster on the cleavage face. It is a hydrous silicate of alumina and lime.

k. -- Indian red. (a) A purplish red earth or pigment composed of a silicate of iron and alumina, with magnesia. It comes from the Persian Gulf. Called also Persian red. (b) See Almagra. -- Indian rice (Bot.), a reedlike water grass. See Rice. -- Indian shot (Bot.), a plant of the genus Canna (C. Indica). The hard b…

A silicate of alumina, iron, and magnesia, having a bright blue color and vitreous luster; cordierite. It is remarkable for its dichroism, and is also called dichroite.

A fibrous mineral occurring in tufts of a straw-yellow color. It is a hydrous silicate of alumina and manganese.

A mineral, of a white color and vitreous luster. It is a hydrous silicate of alumina and lime. Exposed to the air, it loses water, becomes opaque, and crumbles. [Written also laumonite.]

a fine azure-blue color, usually in small rounded masses. It is essentially a silicate of alumina, lime, and soda, with some sodium sulphide, is often marked by yellow spots or veins of sulphide of iron, and is much valued for ornamental work. Called also lapis lazuli, and Armenian stone.