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CHABAZITE , a See also:mineral See also:species belonging to the See also:group of See also:zeolites. It occurs as 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 to flesh-red crystals which vary from transparent to translucent and have a vitreous lustre. The crystals are See also:rhombohedral, and the predominating See also:form is often a rhombohedron (r) with interfacial angles of -85° 14'; they therefore closely resemble cubes in See also:appearance, and the mineral was in fact See also:early (in 1772) described as a cubic zeolite. A characteristic feature is the twinning, the crystals being frequently interpenetration twins with the See also:principal See also:axis as twin-axis
(See also:figs. 1, 2). The appearance shown in fig. 1, with the corners of small crystals in twinned position projecting from the faces r of the See also:main crystal, is especially characteristic of chabazite. Such See also:groups resemble the interpenetrating twinned cubes of fluorspar, but the two minerals are readily distinguished by their cleavage, fluorspar having a perfect octahedral cleavage truncating the corners of the See also:cube, whilst in chabazite there are less distinct cleavages parallel to the rhombohedral (cube-like) faces. Another type of twinned crystal is represented in fig. 2, in which the predominating form is an obtuse hexagonal See also:pyramid (t); the faces of these flatter crystals are often rounded, giving rise to lenticular shapes, hence the name phacolite (from (Paths, a See also:lentil) for this variety of chabazite.
The hardness of chabazite is 42, and the specific gravity 2•o8-2•I6. As first noticed by See also:Sir See also:David See also:Brewster in 183o, the crystals often exhibit anomalous See also:optical characters: instead of being uniaxial, a basal See also:section may be divided into sharply-defined biaxial sectors. See also:Heating of the crystals is attended by a loss of See also:water and a See also:change in their optical characters; it is probable therefore that the anomalous optical characters are dependent on the amount of water See also:present.
Besides phacolite, mentioned above, other varieties of chabazite are distinguished. Herschelite and seebachite are essentially the same as phacolite. Haydenite is the name given to small yellowish crystals, twinned on a rhombohedron See also:plane r, from See also:- JONES
- JONES, ALFRED GILPIN (1824-1906)
- JONES, EBENEZER (182o-186o)
- JONES, ERNEST CHARLES (1819-1869)
- JONES, HENRY (1831-1899)
- JONES, HENRY ARTHUR (1851- )
- JONES, INIGO (1573-1651)
- JONES, JOHN (c. 1800-1882)
- JONES, MICHAEL (d. 1649)
- JONES, OWEN (1741-1814)
- JONES, OWEN (1809-1874)
- JONES, RICHARD (179o-1855)
- JONES, SIR ALFRED LEWIS (1845-1909)
- JONES, SIR WILLIAM (1746-1794)
- JONES, THOMAS RUPERT (1819– )
- JONES, WILLIAM (1726-1800)
Jones's Falls near See also:Baltimore in See also:Maryland. Acadialite is a reddish chabazite from Nova See also:Scotia (the old See also:French name of which is See also:Acadie).
Chemically, chabazite' is a complex hydrated See also:calcium and See also:sodium silicate, with a small proportion of the sodium replaced by See also:potassium, and sometimes a small amount of the calcium replaced by See also:barium and See also:strontium. The See also:composition is however variable,and is best expressed as an isomorphous mixture of the molecules (Ca, Nae)Al2(SiO4)2+41120 and (Ca,Na2)Al2(Si3Os)2d-8H20, which are analogous to the felspars. Most analyses correspond with a See also:formula midway -between these extremes, namely, (Ca,Na2) Al2 (SiO3) 4+6H20.
Chabazite occurs with other zeolites in the amygdaloidal cavities of basaltic rocks; occasionally it has been found in gneisses and See also:schists. Well-formed crystals are known from many localities; for example, Kilmalcolm in See also:Renfrewshire, the See also:Giant's See also:Causeway in Co. See also:Antrim, and See also:Oberstein in See also:Germany. Beautiful, clear glassy crystals of the phacolite (" seebachite ") variety occur with See also:phillipsite and radiating bundles of 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 See also:calcite in cavities in compact See also:basalt near See also:Richmond, See also:Melbourne, See also:Victoria. Small crystals have been observed lining the cavities of fossil shells from See also:Iceland, and in the See also:recent deposits of the hot springs of Plombieres and Bourbonne-See also:les-Bains in See also:France.
Gmelinite and levynite are other species of zeolites which may be mentioned here, since they are closely related to chabazite, and like it are rhombohedral and frequently twinned. Gmelinite forms large flesh-red crystals usually of hexagonal See also:habit, and was early known as soda-chabazite, it having the composition of chabazite but with sodium predominating over calcium (Na2,Ca)Al2(SiO3)46H20. The formula of levynite is CaAl2SiaO1o+5H20. (L. J.
End of Article: CHABAZITE
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