Structural classification Identified zeolitic phases Heulandite
group (C4-C4-T1) stellerite, stilbite, stellerite-Na, Stilbite-Ca Chabazite group (C6) chabazite, levyne, chabazite-Ca, chabazite-Na Analcime group (C4-C4) analcime, wairakite, analcime-Mg Natrolite group (C4-T1) natrolite, thomsonite, thomsonite-Ca Phillipsite group (C4) phillipsite, phillipsite-Na Laumontite group (C8) laumontite
was not found in this part of the mineralized zone.
The magnitude of N[H.sub.4.sup.+] adsorption would be exacerbated by the presence of soil materials with a strong preference for N[H.sub.4.sup.+] such as heulandite
in Zeolite (Ming and Mumpton 1989) and 2:1 layer aluminosilicates (Barbayiannis et al.
Because of the difficulty of discriminating accurately heulandite
from clinoptilolite, we use the term "heulandite
" to include both minerals.
Datolite and prehnite are still present; however, albite and calcite become more common, as do the zeolites heulandite
Prehnite, apophyllite, calcite, hematite, heulandite
and sulfides are known to form on the crystal faces.
If you have a hundred specimens of heulandite
in your collection, unless you run a test on every single specimen you cannot reliably assign to them their correct modern names.
Calcite crystals typically cover first-generation crystals of heulandite
, and are themselves covered by later mordenite.
The delicate "feathers" densely populate the matrix plates, on which pinkish crusts of heulandite
also host pale green, blocky fluorapophyllite crystals to 2 cm.
Early in 2005, a dealer in Changsha offered a specimen, presumably of heulandite
, from a new discovery at Fengjiashan.
Bright orange to red-orange, smooth-surfaced, radial-aggregate spheres of ferrierite crystals with a medium to dull luster reach 2.5 cm in diameter; the spheres line seams in basalt, associated with microcrystals of heulandite
Spence (1920) noted the presence of stilbite and heulandite
in fluorapatite-phlogopite skarn deposits, and Hoffman (1901) reported faujasite from the Daisy mine, Papineau Co., Quebec.