Truscottite: Composition and Ionic Substitutions

E. E. Lachowski, L. W. Murray and H. F. W. Taylor
Department of Chemistry, University of Aberdeen, Scotland

Summary: Eleven specimens of natural or synthetic truscottite or gyrolite-truscottite intergrowth were studied by analytical electron microscopy and X-ray powder diffraction. The results suggest that, in absence of substitution, the formula of truscottite is Ca14 (Si24O58)(OH)8 · ∼ 2H2O. Truscottite can accommodate Al and K in absence of each other to the extents of 1.4 atoms of Al or 0.5 atoms of K in the above formula. Substitution of Al causes a small increase in cell dimensions, which can approach those of reyerite, but substitution of K has negligible effect.

Mineralogical Magazine; September 1979 v. 43; no. 327; p. 333-336; DOI: 10.1180/minmag.1979.043.327.03
© 1979, The Mineralogical Society
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