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A rare metallic element, of uncertain identification, supposed to exist in certain minerals, as gadolinite and samarskite, with other rare ytterbium earth. Symbol Tr or Tb. Atomic weight 150.

hich the constituent parts are united; structure; as, the texture of earthy substances or minerals; the texture of a plant or a bone; the texture of paper; a loose or compact texture.

A rare metallic element of the aluminium group found in some minerals, as certain pyrites, and also in the lead-chamber deposit in the manufacture of sulphuric acid. It is isolated as a heavy, soft, bluish white metal, easily oxidized in moist air, but preserved by keeping under water. Symbol Tl. Atomic weight 203.7.…

Anhydrous sodium sulphate, a mineral of a white or brown color and vitreous luster.

A zeolitic mineral, occurring generally in masses of a radiated structure. It is a hydrous silicate of aluminia, lime, and soda. Called also mesole, and comptonite.

A mineral of a brown to black color, or, as in the variety orangite, orange-yellow. It is essentially a silicate of thorium.

A metallic element found in certain rare minerals, as thorite, pyrochlore, monazite, etc., and isolated as an infusible gray metallic powder which burns in the air and forms thoria; -- formerly called also thorinum. Symbol Th. Atomic weight 232.0.

are metallic element of uncertain properties and identity, said to have been found in the mineral gadolinite.

A mineral occurring as an aggregation of minute scales having an olive-green color and pearly luster. It is a hydrous silicate of aluminia and iron.

luster, obtained in South Africa and much used for ornament. It is an altered form of the mineral crocidolite. See Crocidolite.

An elementary substance found as an oxide in the mineral cassiterite, and reduced as a soft white crystalline metal, malleable at ordinary temperatures, but brittle when heated. It is not easily oxidized in the air, and is used chiefly to coat iron to protect it from rusting, in the form of tin foil with mercury to for…

Pertaining to, or containing, titanium; as, a titanitic mineral.

An elementary substance found combined in the minerals manaccanite, rutile, sphene, etc., and isolated as an infusible iron- gray amorphous powder, having a metallic luster. It burns when heated in the air. Symbol Ti. Atomic weight 48.1.

A mineral occurring in rhombic prisms, generally yellowish and pellucid, also colorless, and of greenesh, bluish, or brownish shades. It sometimes occurs massive and opaque. It is a fluosilicate of alumina, and is used as a gem.

One of the mineral concretions about the joints, and in other situations, occurring chiefly in gouty persons. They consist usually of urate of sodium; when occurring in the internal organs they are also composed of phosphate of calcium.

A mineral occurring in emerald-green tabular crystals having a micaceous structure. It is a hydrous phosphate of uranium and copper. Called also copper uranite, and chalcolite.

A mineral occurring usually in three-sided or six-sided prisms terminated by rhombohedral or scalenohedral planes. Black tourmaline (schorl) is the most common variety, but there are also other varieties, as the blue (indicolite), red (rubellite), also green, brown, and white. The red and green varieties when transpare…

To trace, as a lode or any mineral appearance, to its head. To train a gun (Mil. & Naut.), to point it at some object either forward or else abaft the beam, that is, not directly on the side. Totten. -- To train, or To train up, to educate; to teach; to form by instruction or practice; to bring up. Train up a child in…

A mineral of a grayish-green or bluish color, consisting of the phosphates of iron, manganese, and lithia.

A mineral of a dark brown color, generally with a fibrous, massive structure. It is a fluophosphate of iron and manganese.