ALUNITE, or ALUMSTONE
This article appears in Volume V01, Page 773 of the Encyclopedia Britannica.
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Encyclopedia Britannica - Main :: ALM-ANC
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ALUNITE, or ALUMSTONE , a mineral first observed in the 15th century at Tolfa, near Rome, where it is mined for the manufacture of alum. Extensive deposits are also worked in Tuscany and Hungary , and at Bulladelah in New South Wales. By repeatedly roasting and lixiviating the mineral , alum is obtained in solution, and this is crystallized out by evaporation. Alunite occurs as seams in trachytic and allied volcanic rocks, having been formed by the action of sulphureous vapours on
these rocks. The white See Also: - WHITE
- WHITE, ANDREW DICKSON (1832– )
- WHITE,
GILBERT See Also: - GILBERT
- GILBERT (KINGSMILL) ISLANDS
- GILBERT (or GYLBERDE), WILLIAM (1544-1603)
- GILBERT, ALFRED (1854– )
- GILBERT, ANN (1821-1904)
- GILBERT, GROVE KARL (1843– )
- GILBERT, J
- GILBERT, JOHN (1810-1889)
- GILBERT, MARIE DOLORES ELIZA ROSANNA [" LOLA MONTEZ "] (1818-1861)
- GILBERT, NICOLAS JOSEPH LAURENT (1751–1780)
- GILBERT, SIR HUMPHREY (c. 1539-1583)
- GILBERT, SIR JOSEPH HENRY (1817-1901)
- GILBERT, SIR WILLIAM SCHWENK (1836– )
(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)
, finely granular masses somewhat resemble limestone in appearance , and the more compact kinds from Hungary are so hard and tough that they are used for millstones. Distinct crystals of alunite are rarely met with in cavities in the massive material;
these are rhombohedra with interfacial angles of 9o 50', so that they resemble cubes in appearance . Minute glistening crystals have also been found loose in cavities in altered rhyolite. The hardness is 4 and the specific gravity 2.6. The mineral is a hydrated basic aluminium and potassium sulphate, KAl3(SO4)2(OH)5. It is insoluble in water, but soluble in sulphuric acid. First called aluminilite by J. C. Delametherie in 1797, this name was contracted by F. S. Beudant in 1824 to alunite. (L. J. S.)
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