analcime


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Related to analcime: heulandite

analcime

[ə′nal‚sēm]
(mineralogy)
NaAlSi2O6·H2O A white or slightly colored isometric zeolite found in diabase and in alkali-rich basalts. Also known as analcite.
References in periodicals archive ?
Analcime crystals displaying intergrowth and typical isometric morphology (up to 1.
Figure 7 illustrates representative zeolites diffraction patterns and associated phases Figure 7a reveals a typical assemblage of analcime and chabazite-Ca, accompanied by nontronite.
No regional zoning of zeolite assemblages was apparent in this study Figure 8 shows that the zoning sequence and textural evidence suggest the following crystallisation sequence: first K-rich clay (nontronite) followed by K-rich mica (celadonite), carbonate (calcite), cryptocrystalline silica (e g chalcedony), then thomsonite followed by chabazite, analcime, phillipsite and wairakite, and natrolite, laumontite, and stilbite-type minerals (stilbite and stellerite) Zeolites' stability ields are known from modern hydrothermal systems (Kristmannsdottir and Tomasson, 1978) and the observed sequence in the samples studied here conformed to a progressive decrease in temperature favouring hydrothermal system hydration.
2+] ions and so leaving the water comparatively enriched in alkalies Both celadonite precipitation (which increased the Na+/K+ ratio in solution) and decreased temperature (which favoured Na enrichment in the solution) may have contributed to analcime crystallisation and that of other Narich zeolites (Alt and Honnorez, 1984).
The Si activity decreased during alteration and temperature increased to 200 [degrees]C thereby allowing analcime formation followed by that of natrolite, gonnardite, thomsonite, scolecite and mesolite Laumontite and stilbite formation could be attributed to the presence of Ca, Ba, and Sr-rich hydrothermal fluids produced by a late event, taking into account that these zeolites usually appear filling basalt fractures
1] covers a significant area in the finger print region in the IR spectrum where illite 980 (m), 794 (w); albite 1094 (w), 981 (w), 742 (w); and analcime 976 (m), 736 (w) give prominent bands (Table 2).
Specified weight percentage ranges of minerals and kerogen Mineral Lower Upper limit, % limit, % Nahcolite 0 30 Dawsonite 0 15 Quartz 20 35 Alabite 5 15 Dolomite 5 30 Illite 0 25 Analcime 0 15 Kerogen 0 25 Table 2.
At Two Islands, the larger island is entirely basalt and has common gmelinite and analcime.
They are "heulandite" (heulandite sensu stricto and clinoptilolite), chabazite, analcime, stilbite, barrerite, epistilbite, gmelinite, laumontite, natrolite, mesolite, scolecite, stellerite, tetranatrolite, thomsonite, and wairakite.
Wairakite is generally vitreous with well formed pseudo-octahedral to pseudo-icositetrahedral colourless crystals that can be confused with analcime (Fig.
Stilbite, "heulandite", and analcime are common, natrolite and thomsonite are rare.
Analcime to analcime + "heulandite" to natrolite to calcite.