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Sc2Si2O7
Monoclinic
Thortveitite, a scandium silicate mineral, is a very rare mineral at Sterling Hill and has not been found at Franklin. It was found, in 20-micron crystals, as inclusions within a chromian zincian hercynite (with Fe > Zn) which is rimmed by chromian ferroan gahnite (with Zn > Fe) (Dunn and Frondel, 1990). This thortveitite, like those from many other occurrences, has minor Y substituting for Sc. Microprobe analysis gave Sc2O3 50, SiO2 45, Y2O3 4, total = 99 wt. %. Frondel (1970) provided data on the Sc content of the ores and calcium silicate units and reported maximum concentrations in andradite, pyroxenes, and amphiboles. It may be that this Sc is hosted, at least in part, as thortveitite inclusions. The gahnite/hercynite crystals which serve as a matrix for thortveitite are from the corundum/margarite assemblage in the Franklin Marble near the Sterling Hill orebody and are discussed under corundum and margarite.
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| Copyright © 1995 by Pete J. Dunn |
Website
by Herb Yeates
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Link
to homepage
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This
page created: January 11, 2001 |
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