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PARISITE , a rare See also:mineral, consisting of See also:cerium, lanthanum, See also:didymium and See also:calcium fluo-carbonate, (CeF)2Ca(See also:COs),. It is found only as crystals, which belong to the hexagonal See also:system and usually have the See also:form of acute See also:double pyramids terminated by the basal planes; the faces of the hexagonal pyramids are striated horizontally, and parallel to the basal See also:plane there is a perfect cleavage. The crystals are See also:hair-See also:- BROWN
- BROWN, CHARLES BROCKDEN (1771-181o)
- BROWN, FORD MADOX (1821-1893)
- BROWN, FRANCIS (1849- )
- BROWN, GEORGE (1818-188o)
- BROWN, HENRY KIRKE (1814-1886)
- BROWN, JACOB (1775–1828)
- BROWN, JOHN (1715–1766)
- BROWN, JOHN (1722-1787)
- BROWN, JOHN (1735–1788)
- BROWN, JOHN (1784–1858)
- BROWN, JOHN (1800-1859)
- BROWN, JOHN (1810—1882)
- BROWN, JOHN GEORGE (1831— )
- BROWN, ROBERT (1773-1858)
- BROWN, SAMUEL MORISON (1817—1856)
- BROWN, SIR GEORGE (1790-1865)
- BROWN, SIR JOHN (1816-1896)
- BROWN, SIR WILLIAM, BART
- BROWN, THOMAS (1663-1704)
- BROWN, THOMAS (1778-1820)
- BROWN, THOMAS EDWARD (1830-1897)
- BROWN, WILLIAM LAURENCE (1755–1830)
brown in See also:colour and are translucent. The hardness is 41 and the specific gravity 4.36. See also:Light which has traversed a crystal of parisite exhibits a characteristic absorption spectrum. Until recently the only_ known occurrence of this mineral was in the famous See also:emerald mine at Muzo in See also:Colombia, See also:South See also:America, where it was found by J. J. See also:Paris, who re-discovered and worked the mine in the See also:early See also:part of the 19th See also:century; here it is associated with emerald in a bituminous See also:limestone of Cretaceous See also:age (see
EMERALD).
Closely allied to parisite, and indeed first described as such, is a mineral from the See also:nepheline-See also:syenite See also:district of Julianehaab in south See also:Greenland. To this the name synchysite (from Gr. uvryxuons, confounding) has been given. The crystals are See also:rhombohedral (as distinct from hexagonal; they have the See also:composition CeFCa(CO3)2, and specific gravity 2.90. At the same locality there is also found a See also:barium-parisite, which differs from the Colombian parisite in containing barium in See also:place of calcium, the See also:formula being (CeF)2Ba(CO3)3: this is named cordylite on See also:account of the See also:club-shaped form (KOpbbXtl) a club) of its hexagonal crystals. Bastnasite is a cerium lanthanum and didymium fluo-carbonate (CeF)COa, from Bastnas, near Riddarhyttan, in Vestmanland, See also:Sweden, and the See also:Pike's See also:Peak region in See also:Colorado, U.S.A. (L. J.
End of Article: PARISITE
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