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ENSTATITE , a See also: rock-forming See also:mineral belonging to the See also:group of orthorhombic pyroxenes. It is a See also:magnesium metasilicate, MgSiO3, often with a little See also:iron replacing the magnesium: as the iron increases in amount there is a transition to See also:bronzite (q.v.), and with still more iron to See also:hypersthene (q.v.). Bronzite and hypersthene were known See also:long before enstatite, which was first described by G. A. See also:Kenngott in 1855, and named from ivgTaTi S, " an opponent," because the mineral is almost in-fusible before the See also:blowpipe: the material he described consisted of imperfect prismatic crystals, previously thought to be See also:scapolite, from the See also:serpentine of See also:Mount Zdjar near Schonberg in See also:Moravia. Crystals suitable for goniometric measurement were later found in the See also:meteorite which See also:fell at Breitenhach in the See also:Erzgebirge, Bohemia. Large crystals, a See also:foot in length and mostly altered to steatite, were found in 1874 in the See also:apatite See also:veins traversing See also:mica-schist and See also:hornblende-schist at the apatite mine of Kjorrestad, near Brevig in See also:southern See also:Norway. Isolated crystals are of rare occurrence, the mineral being usually found as an essential constituent of igneous rocks; either as irregular masses in plutonic rocks (norite, See also:peridotite, See also:pyroxenite, &c.) and the serpentines which have resulted by their alteration, or as small idiomorphic crystals in volcanic rocks (See also:trachyte, See also:andesite). It is also a See also:common constituent of meteoric stones, forming with See also:olivine the bulk of the material: here it often forms small spherical masses, or chondrules, with an See also:internal radiated structure.
Enstatite and the other orthorhombic pyroxenes are distinguished from those of the See also:monoclinic See also:series by their See also:optical characters, viz. straight extinction, much weaker See also:double See also:refraction and stronger pleochroism: they have prismatic cleavages (with an See also:angle of S8° 16') as well as planes of parting parallel to the planes of symmetry in the ,See also:prism-See also:zone. Enstatite is 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, greenish or 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; its hardness is 51, and sp. gr. 3.2—3.3. (L. J.
End of Article: ENSTATITE
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