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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.

trary name or character; -- opposed to analogous. Antilogous pole (Eccl.), that pole of a crystal which becomes negatively electrified when heated.

An anomalous state of refraction caused by the absence of the crystalline lens, as after operations for cataract. The remedy is the use of powerful convex lenses. Dunglison.

A crystalline alkaloid obtained from morphia. It is a powerful emetic.

humor (Anat.), one the humors of the eye; a limpid fluid, occupying the space between the crystalline lens and the cornea. (See Eye.) -- Aqueous rocks (Geol.), those which are deposited from water and lie in strata, as opposed to volcanic rocks, which are of igneous origin; -- called also sedimentary rocks.…

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.

Resembling a tree; becoming woody in stalk; dendritic; having crystallizations disposed like the branches and twigs of a tree. "Arborescent hollyhocks." Evelyn.

A crystallized substance, resembling camphor, obtained from the Asarum Europæum; -- called also camphor of asarum.

A white, nitrogenous, crystallizable substance, C4H8N2O3+H2O, found in many plants, and first obtained from asparagus. It is believed to aid in the disposition of nitrogenous matter throughout the plant; -- called also altheine.

A white crystalline compound of acetyl and salicylic acid used as a drug for the salicylic acid liberated from it in the intestines.

An optical property of some crystals which exhibit a star- shaped by reflected light, as star sapphire, or by transmitted light, as some mica.

An oxychloride of copper, usually in emerald-green prismatic crystals.

A poisonous, white, crystallizable alkaloid, extracted from the Atropa belladonna, or deadly nightshade, and the Datura Stramonium, or thorn apple. It is remarkable for its power in dilating the pupil of the eye. Called also daturine.

A hydrous carbonate of copper and zinc, found in pale green or blue crystalline aggregations. It yields a kind of brass on reduction.

A lemon-yellow phosphate of uranium and calcium occurring in tabular crystals with basal cleavage, and in micalike scales. H., 2- 2.5. Sp. gr., 3.05-3.19.

A crystalline globulin, contained in oat kernels, very similar in composition to excelsin, but different in reactions and crystalline form.

a variety of oligoclase with internal firelike reflections due to the presence of minute crystals, probably of hematite; sunstone.

A borosilicate of alumina, iron, and lime, commonly found in glassy, brown crystals with acute edges.

e of several imaginary lines, assumed in describing the position of the planes by which a crystal is bounded.