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LIMBURGITE , in See also:petrology, a dark-coloured volcanic See also:rock resembling See also:basalt in See also:appearance, but containing normally no See also:felspar. The name is taken from See also:Limburg (See also:Germany), where they occur in the well-known rock of the Kaiserstuhi. They consist essentially of See also:olivine and See also:augite with a brownish glassy ground See also:mass. The augite may be See also:green, but more commonly is 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 See also:violet; the olivine is usually See also:pale green or colourless, but is sometimes yellow (hyalosiderite). In the ground mass a second See also:generation of small eumorphic augites frequently occurs; more rarely olivine is See also:present also as an ingredient of the See also:matrix. The See also:principal See also:accessory minerals are titaniferous See also:iron oxides and See also:apatite. Felspar though sometimes present is never abundant, and See also:nepheline also is unusual. In some limburgites large phenocysts of dark brown See also:hornblende and See also:biotite are found, mostly with irregular See also:borders blackened by resorption; in others there are large crystals of soda See also:orthoclase or anorthoclase. Hauyne is an ingredient of some of the limburgites of the Cape Verde Islands.• Rocks of this See also:group occur in considerable See also:numbers in Germany (See also:Rhine See also:district) and in Bohemia, also in See also:Scotland, See also:Auvergne, See also:Spain, See also:Africa (See also:Kilimanjaro), See also:Brazil, &c. They are associated principally with basalts, nepheline and See also:leucite basalts and monchiquites. From the last-named rocks the limburgites are not easily separated as the two classes See also:bear a very See also:close resemblance in structure and in See also:mineral See also:composition, though many authorities believe that the ground mass of the monchiquites is not a See also:glass but crystalline See also:analcite. Limburgites may occur as flows, as sills or dykes, and are sometimes highly vesicular. Closely allied to them are the augitites, which are distinguished only by the See also:absence of olivine; examples are known from Bohemia, Auvergne, the See also:Canary Islands, See also:Ireland, &c.
End of Article: LIMBURGITE
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