An anomalous phillipsite from Saint-Jean-le-Centenaire, Ardeche

Phillipsite [12174-18-4] occurs as clear transparent spheroids, colorless to yellow to reddish-orange in color, in the vugs of a basalt at Saint-Jean-le-Centenaire, Ardeche, France. The fibrous radial nature of the spheroids can be obsd. under the microscope only between crossed polars. It has a higher content of Si than the normal hydrothermal (i.e. those occurring in vugs of massive rocks) phillipsites. The powder pattern lacks all those peaks which make the distinction between phillipsite and merlinoite possible. The peak broadening in the powder pattern indicates a crystallite size of ∼350 Å. This anomalous zeolite is more similar to phillipsite than to merlinoite; its features are near those of some sedimentary and some synthetic phillipsites.