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NATROLITE , a See also:mineral See also:species belonging to the zeolite See also:group.
It is a hydrated See also:sodium and See also:aluminium silicate with the See also:formula
Na2Al2Si3O1o•2H2O, and containing sodium (Na2O, 16.3%),
was named natrolite by M. H. See also:Klaproth in 1803. " See also:Needle-
See also:- STONE
- STONE (0. Eng. shin; the word is common to Teutonic languages, cf. Ger. Stein, Du. steen, Dan. and Swed. sten; the root is also seen in Gr. aria, pebble)
- STONE, CHARLES POMEROY (1824-1887)
- STONE, EDWARD JAMES (1831-1897)
- STONE, FRANK (1800-1859)
- STONE, GEORGE (1708—1764)
- STONE, LUCY [BLACKWELL] (1818-1893)
- STONE, MARCUS (184o— )
- STONE, NICHOLAS (1586-1647)
stone " or " needle-zeolite " are other names, alluding to the
See also:common acicular See also:habit of the crystals, which are often very
slender and are aggregated in divergent tufts. Larger crystals
have the See also:form of a square See also:prism terminated by a See also:low See also:pyramid:
the prism See also:angle being nearly a right angle (88° 452'), the crystals
are tetragonal in See also:appearance, though actually orthorhombic.
There are perfect cleavages parallel to the faces of the prism.
1 E. See also:- THOMAS
- THOMAS (c. 1654-1720)
- THOMAS (d. 110o)
- THOMAS, ARTHUR GORING (1850-1892)
- THOMAS, CHARLES LOUIS AMBROISE (1811-1896)
- THOMAS, GEORGE (c. 1756-1802)
- THOMAS, GEORGE HENRY (1816-187o)
- THOMAS, ISAIAH (1749-1831)
- THOMAS, PIERRE (1634-1698)
- THOMAS, SIDNEY GILCHRIST (1850-1885)
- THOMAS, ST
- THOMAS, THEODORE (1835-1905)
- THOMAS, WILLIAM (d. 1554)
Thomas, Histoire See also:des ateliers nationaux, p. 29.
273
The mineral also often occurs in compact fibrous aggregates, the See also:fibres having a divergent or radial arrangement (hence the name radiolite for one variety). From other fibrous See also:zeolites natrolite is readily distinguished by its See also:optical characters: between crossed nicols the fibres extinguish parallel to their length, and they do not show an optic figure in convergent polarized See also:light. Natrolite is usually 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 or colourless, but some-times reddish or yellowish. The lustre is vitreous, or in finely fibrous specimens sometimes silky. The spec. See also:- GRAY
- GRAY (or GREY), WALTER DE (d. 1255)
- GRAY, ASA (1810-1888)
- GRAY, DAVID (1838-1861)
- GRAY, ELISHA (1835-1901)
- GRAY, HENRY PETERS (1819-18/7)
- GRAY, HORACE (1828–1902)
- GRAY, JOHN DE (d. 1214)
- GRAY, JOHN EDWARD (1800–1875)
- GRAY, PATRICK GRAY, 6TH BARON (d. 1612)
- GRAY, ROBERT (1809-1872)
- GRAY, SIR THOMAS (d. c. 1369)
- GRAY, THOMAS (1716-1771)
gray. is 2.2, and the hardness 52. The mineral is readily fusible, melting in a See also:candle-See also:flame, to which it imparts a yellow See also:colour owing to the presence of sodium. It is decomposed by hydrochloric See also:acid with separation of gelatinous See also:silica.
Natrolite occurs with other zeolites in the amygdaloidal cavities of basic igneous rocks. The best specimens are the diverging See also:groups of white prismatic crystals found in compact See also:basalt at the See also:Puy-de-Marman, Puy-de See also:Dome, See also:France. The largest crystals are those from Brevig in See also:Norway. The walls of cavities in the basalt of the See also:Giant's See also:Causeway, in Co. See also:Antrim, are frequently encrusted with slender needles of natrolite, and similar material is found abundantly in the volcanic rocks (basalt and See also:phonolite) of Salesel, See also:Aussig and several other places in the See also:north of Bohemia.
Several varieties of natrolite have been distinguished by See also:special names. Fargite is a red natrolite from Glenfarg in See also:Perthshire. Bergmannite or Spreustein is an impure variety which has resulted by the alteration of other minerals, chiefly See also:sodalite, in the augitesyenite of See also:southern Norway.
End of Article: NATROLITE
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