Home > American Minerals – August 22 > MS1422 Tilleyite


Tilleyite is a calcium silicate carbonate. Larsen & Dunham (1933) named the mineral in honor of Cecil Edgar Tilley (1894-1973), petrologist at Cambridge University (England). Tilleyite forms under rather special metamorphic conditions of high temperature combined with low concentrations of both aluminum and iron. Its off white color likely stems from electronic defects caused by strain deformation.

This sample contains a band of very pale lavender tilleyite cleavages. The matrix consists of massive gary-green vesuvianite, and a bit of blue calcite. Type locality. Collecting at Crestmore seems to have ceased more than a decade ago, possibly when TXI took ownership of the quarry ca. 1999.

Price: $40

Item code: MS1422

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