Home > Type Localities I – June 9 > MS1091 Esperite, Willemite

Esperite, Willemite

Esperite is a calcium lead zinc silicate. Palache et al. (1928) and Palache et al. (1928) originally noted the mineral at Franklin, then calling it "calcium larsenite". Later study and redefinition by Moore & Ribbe (1965) distinguished the species from larsenite, renaming the mineral in honor of Esper Signius Larsen, Jr. (1879-1961), American petrologist and mineralogist at Harvard University. The mineral formula and symmetry remained poorly defined until Tait et al. (2010) found an untwinned crystal and solved the crystal structure. Esperite forms by alteration of primary hardystonite, and is a classic part of the "Parker Shaft" mineral suite. This is a rich example with minor willemite and black franklinite in association. Esperite fluoresces lemon yellow while willemite fluoresces yellow green under shortwave ultraviolet radiation.

Price: $350

Item code: MS1091

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