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The rim which encompasses and fastens a jewel or other object, as the crystal of a watch, in the cavity in which it is set.

A name applied to the amorphous or crystalline mass obtained from bile by the action of alcohol and ether. It is composed of a mixture of the sodium salts of the bile acids.

g iron and magnesia, generally of a black or dark green color; -- a common constituent of crystalline rocks. See Mica.

placed base to base; having a pyramid at each of the extremities of a prism, as in quartz crystals.

The line bisecting the angle between the optic axes of a biaxial crystal.

One of the elements; a metal of a reddish white color, crystallizing in rhombohedrons. It is somewhat harder than lead, and rather brittle; masses show broad cleavage surfaces when broken across. It melts at 507º Fahr., being easily fused in the flame of a candle. It is found in a native state, and as a constituent of…

A white, crystalline, nitrogenous substance, C2O2N3H5, formed by heating urea. It is intermediate between urea and cyanuric acid.

Blue verditer. See Verditer. -- Blue vitriol (Chem.), sulphate of copper, a violet blue crystallized salt, used in electric batteries, calico printing, etc. -- Blue water, the open ocean. -- To look blue, to look disheartened or dejected. -- True blue, genuine and thorough; not modified, nor mixed; not spurious; s…

A mineral of a white or gray color occurring massive and in isometric crystals; in composition it is a magnesium borate with magnesium chloride.

A white or gray crystalline salt, with a slight alkaline taste, used as a flux, in soldering metals, making enamels, fixing colors on porcelain, and as a soap. It occurs native in certain mineral springs, and is made from the boric acid of hot springs in Tuscany. It was originally obtained from a lake in Thibet, and wa…

Of, pertaining to, or containing, boron. Boric acid, a white crystalline substance B(OH)3, easily obtained from its salts, and occurring in solution in the hot lagoons of Tuscany.

as a substance of a deep olive color, in a semimetallic form, and in colorless quadratic crystals similar to the diamond in hardness and other properties. It occurs in nature also in boracite, datolite, tourmaline, and some other minerals. Atomic weight 10.9. Symbol B.

Imperfectly crystallized or coarse diamonds, or fragments made in cutting good diamonds which are reduced to powder and used in lapidary work.

A mineral of a steel-gray to black color and metallic luster, occurring crystallized, often in twin crystals shaped like cogwheels (wheel ore), also massive. It is a sulphide of antimony, lead, and copper.

, as of a rhombic prism. Brachydiagonal axis, the shorter lateral axis of an orthorhombic crystal.

A plane of an orthorhombic crystal which is parallel both to the vertical axis and to the shorter lateral (brachydiagonal) axis.

A substance, C16H14O5, extracted from brazilwood as a yellow crystalline powder which is white when pure. It is colored intensely red by alkalies on exposure to the air, being oxidized to bra*sil"e*in, C16H12O5, to which brazilwood owes its dyeing properties.

ance contained in both Brazil wood and Sapan wood, from which it is extracted as a yellow crystalline substance which is white when pure. It is colored intensely red by alkalies. [Written also brezilin.]

A rare zeolitic mineral occurring in white monoclinic crystals with pearly luster. It is a hydrous silicate of aluminia, baryta, and strontia.

sed for polishing cultery; -- originally manufactured at Bristol. -- Bristol stone, rock crystal, or brilliant crystals of quartz, found in the mountain limestone near Bristol, and used in making ornaments, vases, etc. When polished, it is called Bristol diamond.