Home > Franklin Type Species – December 26 > MS1019 Esperite

Esperite - Sold


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) noted differences from larsenite, and renamed 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.

This specimen was part of the personal collection of Ralph Merrill, proprietor of the prolific mail order business Minerals Unlimited. Merrill's collection card and label also ship with the specimen.