Natrolite


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Related to Natrolite: olivine, Scolecite, heulandite, analcime, stilbite

natrolite

[′nā·trə‚līt]
(mineralogy)
Na2 Al2Si3O10·2H2O A zeolite mineral composed of hydrous silicate of sodium and aluminum; usually occurs in slender acicular or prismatic crystals.

Natrolite

 

a mineral of the zeolite family with chemical composition Na2[Al2Si3O10].2H2O; an aluminosilicate, it is classed according to crystallochemical structure as a tectosilicate. Natrolite crystallizes in the orthorhombic and tetragonal systems to form elongated prismatic or acicular crystals; more rarely, it occurs as compact cryptocrystalline masses. It is usually colorless; sometimes it is grayish or yellowish. Natrolite’s hardness on Mohs’ scale measures 5–5.5, and its density is 2,200–2,500 kg/m3.

Natrolite absorbs H2O, NH3, CO2, H2S, and other substances. It is also known for its ability to exchange base ions in solution for base ions in the structure, a property that has found wide application in industry, primarily in the manufacture of artificial zeolites. Natrolite forms in association with other zeolites and with calcite, quartz, and chlorites in the cavities and fissures of igneous rocks by precipitation from hot aqueous solutions. It is also formed as a result of the hydrothermal changes of nepheline and may be found in the weathering zone of nepheline syenites, as well as in contemporary marine deposits.

M. D. DORFMAN

References in periodicals archive ?
The natrolite group (secondary unit C4-T1) was made up of natrolite, thomsonite and thomsonite-Ca.
With natrolite, people have always said you can't get Eu3+ in there," study co-author Thomas Vogt said.
analcime I, Ba-bearing phillipsite-Ca, gismondine, rarely gmeliniteCa) and development of well-defined crystals or fibrous aggregates of natrolite and phillip-site-Ca growing from the walls into open space.
Natrolite is generally beige to white, massive or as radiating fibres, dull, and brittle (Fig.
This member of the chlorite group has also been collected as earthy brown pseudomorphs after analcime and natrolite.
Individual natrolite crystals and groups up to 5 cm long form chaotic, sheaf-like or radial aggregates.
They were already concerned about the difficulty of getting benitoite gem crystals out of the hard, white natrolite without breaking them, and so they packed up a representative chunk of benitoite-rich vein material to ship to L.
Pink and green apophyllites have also been found, as have natrolite specimens showing many different habits.
Willimott (1884) reported chabazite and natrolite from the Haldane Mine and stilbite from the Moore (Seybold) Mine, Gatineau Co.
Other associated minerals include dawsonite, barite, elpidite, natrolite and quartz.
Sporadically, lomonosovite, manaksite and natrolite become rock-forming minerals.
Imagine, for instance, lustrous green brucite crystals to 4 cm from the Ethel mine, Zimbabwe; super-sharp, lustrous black cassiterite crystals to 3 cm from the Kamativi mine, Zimbabwe; wonderful 10-cm clusters of radiating natrolite crystals from the Chrome mine, Limpopo, South Africa--it's like visiting exotic animals in a zoo.