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Having, or characterized by, three unequal axes intersecting at oblique angles. See the Note under crystallization.

A mineral of the feldspar family, triclinic in crystallization, and in composition a silicate of alumina and soda. It is a common constituent of granite and of various igneous rocks. See Feldspar.

A kind of triclinic feldspar found in the Andes.

An eruptive rock allied to trachyte, consisting essentially of a triclinic feldspar, with pyroxene, hornblende, or hypersthene.

A feldspar closely related to orthoclase, but triclinic. It is chiefly a silicate of sodium, potassium, and aluminium. Sp. gr., 2.57 -- 2.60.

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.

A rock of igneous origin, consisting of augite and triclinic feldspar, with grains of magnetic or titanic iron, and also bottle- green particles of olivine frequently disseminated.

A basic, dark-colored, holocrystalline, igneous rock, consisting essentially of a triclinic feldspar and pyroxene with magnetic iron; -- often limited to rocks pretertiary in age. It includes part of what was early called greenstone.

An igneous, crystalline in structure, consisting essentially of a triclinic feldspar and hornblende. It includes part of what was called greenstone.

A dark-colored, basic, igneous rock, composed essentially of pyroxene and a triclinic feldspar with magnetic iron. By many authors it is considered equivalent to a coarse-grained basalt.

A mineral of the feldspar group, like orthoclase or common feldspar in composition, but triclinic in form.

A granular crystalline rock consisting essentially of a triclinic feldspar (as labradorite) and hypersthene.

A triclinic soda-lime feldspar. See Feldspar.

A general term used of any triclinic feldspar. See the Note under Feldspar.

thesis; agglutinative. Polysynthetic twinning (Min.), repeated twinning, like that of the triclinic feldspar, producing fine parallel bands in alternately reversed positions.

Triclinic.

ought about. Polysynthetic twinning, repeated twinning of crystal lamellæ, as that of the triclinic feldspars. -- Repeated twinning, twinning of more than two crystals, or parts of crystals. -- Twinning axis, Twinning plane. See the Note under Twin, n.