Kaolinite appeared towards higher F/R ratios at the expense of the Na-Ca-bearing zeolites such as natrolite and scolecite
. Increasing amounts of anhydrite were formed towards higher F/R ratios in competition with other Ca-bearing minerals such as epidote and wairakite until F/R values of >50 were reached, where all the Ca was consumed by the precipitation of anhydrite.
A sequential formation of zeolites and associated secondary minerals filling amygdales and veins in tertiary basaltic host rocks from the Isle of Skye has been described in this study From early to late formation and, from outermost to innermost portions of the cavities, nontronite, celadonite, thomsonite, phillipsite, chabazite, analcime, natrolite, mesolite, stilbite, scolecite
and laumontite and stilbite were sequentially found However, individual complexly zoned amygdales and veins show evidence of multiple fluid-circulation events, showing a contrast in mineral assemblages from different cavities.
They are "heulandite" (heulandite sensu stricto and clinoptilolite), chabazite, analcime, stilbite, barrerite, epistilbite, gmelinite, laumontite, natrolite, mesolite, scolecite
, stellerite, tetranatrolite, thomsonite, and wairakite.
on Stilbite Ozhar Dist., Nasik, Maharashtra, India 6 1/2" wide
, mesolite, cerussite--such specimens and other fragile delicacies are highly desired by avid mineral collectors.
The powellite crystals are loose, complete floaters, with white sprigs of scolecite
protruding a millimeter or so here and there, and they are razor-sharp, textbook examples of tetragonal bipyramids, with c axes about 1.25 times as long as a and b.
Ca[[Al.sub.2][Si.sub.3][O.sub.10]] x 3[H.sub.2]O
First, there are not-beautiful but very unusual specimens, found very recently in a well-digging near Aurangabad, of what some dealers at Denver were tentatively calling a mixture of scolecite
and mesolite, but which has now been shown to be the zeolite species thomsonite.
A typical cavansite vug is not like the horizontal, level-floored cavities in which apophyllite, heulandite, scolecite
and stilbite are generally found.
They flagged me down and showed me several fine new specimens of powellite, one having a mirror-bright, doubly terminated powellite crystal 2.5 cm across on a spray of scolecite
measuring about 1.25 X 10 cm.
Rare millimeter-size crystals, variably elongated, some of them lozenge-shaped, came from the hydrothermally altered zone near the contact with the talc-chlorite lens in the same environment as the scolecite
and chabazite found in the footwall of the talc-chlorite deposit (Favreau, 1994).
Matrix India (B-36 Abhimanshri Society 411 008 Pune, India) had two of the largest and finest scolecite
specimens ever seen from Maharashtra, India.