OBSERVATION OF TALC-TREMOLITE INTERFACES BY HIGH-RESOLUTION ELECTRON-MICROSCOPY

Talc - a sheet silicate and tremolite - a chain silicate are found by electron microscopy and X-ray microanalysis to occur intergrown as bicrystals with sharp, fault-free boundaries in a talc-rich gemstone nephrite from Scortaseo, Puschlav Valley, Swiss Alps. The plane of intergrowth is the (010)-plane for both components. Curving, stepped interfaces are observed more rarely, and these suggest a reaction from tremolite to talc which stopped before completion. The Mg-ions necessary for this reaction may stem from the associated dolomite rock. © 1979 Springer-Verlag.