Micro-chemical analyses of the studied growths made it possible to characterise the composition of glauconitic micas (glauconite and celadonite
Qualitative XRD analysis led to identifying a variety of zeolite species, including analcime, as the dominant zeolytic phase, followed by chabazite, natrolite, thomsonite, wairakite, stilbite, stilbite-Ca, phillip-site and stellerite-Na, thomsonite-Ca, chabazite-Ca and chabazite-Na, with minor stellerite, laumontite, levyne, phillipsite-Na, and gyrolite Other secondary minerals associated with zeolites were celadonite
(Fe-rich mica), nontronite (Fe-rich smectite), greigeite (iron sulide mineral), koninckite or bobierrite (phosphates), alunite (sulphate), truscottite (silicate), calcite or dolomite, and quartz Nontronite occurred in most samples.
Pure glauconite and celadonite
occur as 1M polytype.
Spatial and temporal variability in crystallization of celadonites
within the Troodos ophiolite, Cyprus: implications for low temperature alteration of the oceanic crust.
Amygdaloidal basalt flows have amygdale fillings principally of celadonite
and silica minerals, with minor amounts of zeolite.
These results are very valuable as some models developed on reactive transport by alkaline fluids in bentonite or argillites predict the formation of a tobermorite layer which induces a porosity closure immediately after the cement interface, where magnesium phases are also formed: celadonite
Pandey also had lustrous crystal groups of yet another new kind of basalt-cavity fluorapophyllite, these also from Aurangabad: lustrous, perfect tetragonal prisms with pyramid and basal faces are tinted deep green by included chlorite (not celadonite
; the celadonite-included heulandite and stilbite crystals from India are paler green and much less lustrous).
5 shows a recently discovered contraction of celadonite
The totals for iron and magnesium ([Fe.sup.2+] + Mg = 0.99; all iron is taken as divalent) show a relatively high substitution through the celadonite
Consulting our Indian Zeolites issue, we see that Shakur is the locality for the well-known cloudy greenish gray heulandite and stilbite crystals which also owe their color to minute, wormlike inclusions of celadonite
. The color of the new powellite specimens is the same, and the species is morphologically unmistakable: very sharp, lustrous pseudo-octahedral crystals to 1 cm, occurring as loose clusters and on matrix with good crystals of the familiar green heulandite.
A last item from India: quarries around Sakur (or Shakur), about 90 km southeast of Nasik, have lately produced another large batch of heulandite crystal specimens tinted pale apple-green to dark green by fine-grained inclusions of celadonite
. National Minerals (see paragraph above) had about 50 beautiful cabinet-sized specimens, with individual heulandite crystals to 5 cm, curved and shiny, standing up well on matrix; some crystals also have dustings of dull brownish black microcrystals of julgoldite.