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CLINTONITE , a See also:group of micaceous minerals known as the " brittle micas." Like the micas and chlorites, they are mono-clinic in See also:crystallization and have a perfect cleavage parallel to the See also:flat See also:surface of the plates or scales, but differ markedly from these in the brittleness of the laminae; they are also considerably harder, the hardness of chloritoid being as high as 61 on See also:Mohs' See also:scale. They differ chemically from the micas in containing less See also:silica and no alkalis, and from the chlorites in containing much less See also:water; in many respects they are intermediate between the micas and chlorites.
The following See also:species are distinguished:
Margarite is a basic See also:calcium See also:aluminium silicate, H2CaAl4Si2O12, and is classed by some authors as a See also:lime-See also:mica. It forms 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 pearly scales, and was at first known as See also:pearl-mica and after-wards as margarite, from µapyapirns, a pearl. It is a characteristic See also:associate of See also:corundum, of which it is frequently an alteration product (facts which suggested the synonymous names corundellite and emerylite), and is found in the See also:emery deposits of See also:Asia See also:Minor and the Grecian See also:Archipelago, and with corundum at several localities in the See also:United States.
Seybertite, Brandisite and Xanthophyllite are closely allied species consisting of basic See also:magnesium, calcium and aluminium silicate, and have been regarded as isomorphous mixtures of a silicate (H2CaM$4Si3O12) and an aluminate (H2CaMgA16O12). Seybertite (the See also:original clintonite) occurs as reddish-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 to See also:copper-red, brittle, foliated masses in metamorphic See also:limestone at Amity, New See also:York; brandisite as yellowish-See also:green hexagonal prisms in metamorphic limestone in the Fassathal, See also:Tirol; xanthophyllite as yellow folia and as distinct crystals (waluewite) in chloride See also:schists in the Urals.
Chloritoid has the See also:formula H2(Fe,Mg)Al2SiOr. It forms See also:tabular crystals and scales, with indistinct hexagonal outlines, which are often curved or See also:bent and aggregated in rosettes. The See also:colour is dark See also:grey or green; a characteristic feature is the pleochroism, the pleochroic See also:colours varying from yellowish-green to See also:indigo-See also:blue. Hardness, 61; specific gravity, 3.4-3.6. It occurs as isolated scales scattered through schistose rocks and phyllites of See also:dynamo-metamorphic origin. The ottrelites of the phyllites and ottrelite-schists of Ottrez and other localities in the Belgian See also:Ardennes is a manganiferous variety of chloritoid, but owing to enclosed impurities the analyses differ widely from those of typical chloritoid. (L. J.
End of Article: CLINTONITE
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