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A transparent variety of calcite, the best of which is obtained in Iceland. It is used for the prisms of the polariscope, because of its strong double refraction. Cf. Calcite.

A massive, compact limestone; a variety of calcite, capable of being polished and used for architectural and ornamental purposes. The color varies from white to black, being sometimes yellow, red, and green, and frequently beautifully veined or clouded. The name is also given to other rocks of like use and appearance,…

mahogany (Bot.) See under Mahogany. -- Mountain meal (Min.), a light powdery variety of calcite, occurring as an efflorescence. -- Mountain milk (Min.), a soft spongy variety of carbonate of lime. -- Mountain mint. (Bot.) See Mint. -- Mountain ousel (Zoöl.), the ring ousel; -- called also mountain thrush and mount…

ly) designating certain compounds of nitrogen or of its acids, as nitrohydrochloric, nitrocalcite; also, designating the group or radical NO2, or its compounds, as nitrobenzene. Nitro group, the radical NO2; -- called also nitroxyl.

ical characters without alteration of chemical composition, as the change of aragonite to calcite.

A variety of calcite, or calcium carbonate, consisting of aggregated globular concretions about the size of a pea; -- called also peastone, peagrit.

axial crystal is said to be optically positive (like quartz), or optically negative (like calcite), or to have positive, or negative, double refraction, according as the optic axis is the axis of least or greatest elasticity for light; a biaxial crystal is similarly designated when the same relation holds for the acute…

al sometimes occuring crystallized, but generally massive with rhombohedral cleavage like calcite; -- called also dialogite.

ed also spiny lobster, and sea crayfish. -- Rock meal (Min.), a light powdery variety of calcite occuring as an efflorescence. -- Rock milk. (Min.) See Agaric mineral, under Agaric. -- Rock moss, a kind of lichen; the cudbear. See Cudbear. -- Rock oil. See Petroleum. -- Rock parrakeet (Zoöl.), a small Australian p…

Satin flower (Bot.) See Honesty, 4. -- Satin spar. (Min.) (a) A fine fibrous variety of calcite, having a pearly luster. (b) A similar variety of gypsum. -- Satin sparrow (Zoöl.), the shining flycatcher (Myiagra nitida) of Tasmania and Australia. The upper surface of the male is rich blackish green with a metallic l…

ry nodule, usually of limestone, intersected within by cracks which are often filled with calcite, barite, or other minerals.

A variety of calcite, so called from its slaty structure; -- called also slate spar.

d; -- applied as a name to various minerals. Calcareous sinter, a loose banded variety of calcite formed by deposition from lime-bearing waters; calcareous tufa; travertine. -- Ceraunian sinter, fulgurite. -- Siliceous sinter, a light cellular or fibrous opal; especially, geyserite (see Geyserite). It has often a pea…

arily parallel to the stratification; foliated rocks. -- Slate spar (Min.), a variety of calcite of silvery white luster and of a slaty structure. -- Transparent slate, a plate of translucent material, as ground glass, upon which a copy of a picture, placed beneath it, can be made by tracing.

ame for a nonmetallic mineral, usually cleavable and somewhat lustrous; as, calc spar, or calcite, fluor spar, etc. It was especially used in the case of the gangue minerals of a metalliferous vein. Blue spar, Cube spar, etc. See under Blue, Cube, etc.

One of the varieties of calcite, barite, and feldspar, which emit a fetid odor on being struck; -- called also swinestone.

onmetalliferous mineral or rock material which accompanies the ores in a vein, as quartz, calcite, barite, fluor spar, etc.; -- called also veinstuff.