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ANHYDRITE , a See also:mineral, differing chemically from the more commonly occurring See also:gypsum in containing no See also:water of See also:crystallization, being anhydrous See also:calcium sulphate, CaSO4. It crystallizes in the orthorhombic See also:system, and has three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic See also:barium and See also:strontium sulphates, as might be expected from the chemical formulae. Distinctly See also:developed crystals are somewhat rare, the mineral usually presenting the See also:form of cleavage masses. The hardness is 32 and the specific gravity 2.9. The See also:colour is See also:- WHITE
- WHITE, ANDREW DICKSON (1832– )
- WHITE, GILBERT (1720–1793)
- WHITE, HENRY KIRKE (1785-1806)
- WHITE, HUGH LAWSON (1773-1840)
- WHITE, JOSEPH BLANCO (1775-1841)
- WHITE, RICHARD GRANT (1822-1885)
- WHITE, ROBERT (1645-1704)
- WHITE, SIR GEORGE STUART (1835– )
- WHITE, SIR THOMAS (1492-1567)
- WHITE, SIR WILLIAM ARTHUR (1824--1891)
- WHITE, SIR WILLIAM HENRY (1845– )
- WHITE, THOMAS (1628-1698)
- WHITE, THOMAS (c. 1550-1624)
white, sometimes greyish, bluish or reddish. On the best developed of the three cleavages the lustre is pearly, on other surfaces it is of the See also:ordinary vitreous type.
Anhydrite is most frequently found in See also:salt deposits with gypsum; it was, for instance, first discovered, in 1794, in a salt mine near See also:- HALL
- HALL (generally known as SCHWABISCH-HALL, tc distinguish it from the small town of Hall in Tirol and Bad-Hall, a health resort in Upper Austria)
- HALL (O.E. heall, a common Teutonic word, cf. Ger. Halle)
- HALL, BASIL (1788-1844)
- HALL, CARL CHRISTIAN (1812–1888)
- HALL, CHARLES FRANCIS (1821-1871)
- HALL, CHRISTOPHER NEWMAN (1816—19oz)
- HALL, EDWARD (c. 1498-1547)
- HALL, FITZEDWARD (1825-1901)
- HALL, ISAAC HOLLISTER (1837-1896)
- HALL, JAMES (1793–1868)
- HALL, JAMES (1811–1898)
- HALL, JOSEPH (1574-1656)
- HALL, MARSHALL (1790-1857)
- HALL, ROBERT (1764-1831)
- HALL, SAMUEL CARTER (5800-5889)
- HALL, SIR JAMES (1761-1832)
- HALL, WILLIAM EDWARD (1835-1894)
Hall in See also:Tirol. Other localities which produce typical specimens of the mineral, and where the mode of occurrence is the same, are See also:Stassfurt in See also:Germany, Aussee in See also:Styria and Bex in See also:Switzerland. At all these places it is only met with at some See also:depth; nearer the See also:surface of the ground it has been altered to gypsum owing to absorption of water.
From an aqueous See also:solution calcium sulphate is deposited as crystals of gypsum, but when the solution contains an excess of See also:sodium or See also:potassium chloride anhydrite is deposited. This is one of the several methods by which the mineral has been prepared artificially, and is identical with its mode of origin in nature, the mineral having crystallized out in salt basins.
The name anhydrite was given by A. G. See also:Werner in 1804, because of the See also:absence of water, as contrasted with the presence of water in gypsum. Other names for the See also:species are muriacite and karstenite; the former, an earlier name, being given under the impression that the substance was a chloride (muriate). A See also:peculiar variety occurring as contorted concretionary masses is known as tripe-See also:- STONE
- STONE (0. Eng. shin; the word is common to Teutonic languages, cf. Ger. Stein, Du. steen, Dan. and Swed. sten; the root is also seen in Gr. aria, pebble)
- STONE, CHARLES POMEROY (1824-1887)
- STONE, EDWARD JAMES (1831-1897)
- STONE, FRANK (1800-1859)
- STONE, GEORGE (1708—1764)
- STONE, LUCY [BLACKWELL] (1818-1893)
- STONE, MARCUS (184o— )
- STONE, NICHOLAS (1586-1647)
stone, and a scaly granular variety, from Vulpino, near See also:Bergamo, in See also:Lombardy, as vulpinite; the latter is cut and polished for ornamental purposes. (L. J.
End of Article: ANHYDRITE
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