, and calcite constitute the stable alteration minerals competing for Ca at low temperature, followed by their progressive replacement by epidote, wairakite, and prehnite with increased temperature.
varies in habit showing bladed crystals, spherulites, radial crystal groups and rich coatings mainly made up of small crystals, although it sometimes has a fibrous nature Analcime appears as vitreous and granular well-formed trapezohedral crystals which are often colourless and sometimes white Natrolite is generally beige to white, either massive or forming radiating fibers and shows a more glassy brightness than mesolite, which is generally milky white and fibrous, having larger fibers than those of natrolite Stilbite commonly occurs as vitreous sheaves or plates, ranging from colourless to green to white
Huvitavad on Thomsonite
kaaslinlase, eestlanna Elsebet Pareki tahelepanekud, kes kirjutas sakslaste lahkumisega seonduvalt jargmiselt:
Two weeks before the 2009 Denver Show, a prospect pit in a forest near Aurangabad, Maharashtra, India yielded about 400 very attractive specimens of what the Indian dealers were quite sure was thomsonite
, although some eyeballing experts (e.g.
Short mineralogical notes on natrolite, thomsonite
, phillipsite, gismondine and analcime assemblages were presented by Muhlstein and Fengl (1977), gmelinite by Barta and Rychly (1979) and Rychly et al.
They are "heulandite" (heulandite sensu stricto and clinoptilolite), chabazite, analcime, stilbite, barrerite, epistilbite, gmelinite, laumontite, natrolite, mesolite, scolecite, stellerite, tetranatrolite, thomsonite
, and wairakite.
Mikhail Anosov of Russian Minerals (one of our new advertisers: email@example.com) had about 20 very good miniature specimens of the fairly rare zeolite thomsonite
, found in summer 2009 in a basalt exposure somewhere on the Amudiha River, 300 km north of Tura, Siberia.
Such crystals are visually similar to thomsonite
Moyd (1949) mentioned zeolites associated with a band of nepheline-bearing rocks in the Bancroft, Ontario area, and Corriveau (1985) noted thomsonite
in an alkalic syenite from Lac Rouge, Labelle Co., Quebec.
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
. Opaque, pale creamy orange thomsonite
spheres and hemispheres rest singly, or are lightly intergrown to form crusts, directly on basalt matrix; the spheres reach 7 cm in diameter, and matrix plates liberally strewn with spheres reach 30 cm across.
Relationship to othe r species: It is a member of the zeolite group, specifically the thomsonite