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CARBONADO , a name given in See also:Brazil to a dark massive See also:form of impure See also:diamond, known also as " carbonate " and in See also:trade simply as See also:carbon. It is sometimes called See also:black diamond. Generally it is found in small masses of irregular polyhedral form, black, 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 or dark-See also:grey in See also:colour, with a dull resinoid lustre; and breaking with a granular fracture, paler in colour,and in some cases much resembling that of See also:fine-grained See also:steel. Being slightly cellular, its specific gravity is rather less than that of crystallized diamond. It is found almost exclusively in the See also:state of See also:Bahia in Brazil, where it occurs in the cascalho or diamond-bearing See also:gravel. See also:Borneo also yields it in small quantity. Formerly of little or no value, it came into use on the introduction of Leschot's diamond-drills, and is now extremely valuable for mounting in the steel crowns used for diamond-See also:boring. Having no cleavage, the carbon is less liable to fracture on the rotation of the See also:drill than is crystallized diamond. The largest piece of carbonado ever recorded was found in Bahia in 1895, and weighed 3150 carats. Pieces of large See also:size are, however, relatively less valuable than those of moderate dimensions, since they require the See also:expenditure of much labour in reducing them to fragments of a suitable size for mounting in the drill-heads. See also:Ilmenite has sometimes been mistaken in the See also:South See also:African mines for carbonado. (F. W.
End of Article: CARBONADO
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