Category Silicate mineral Strunz classification 9.AB.15 Space group P21/m | Formula
(repeating unit) PbCa3Zn4(SiO4)4 Crystal system Monoclinic | |
 | ||
Crystal class Prismatic (2/m)
(same H-M symbol) | ||
Esperite is a rare complex calcium lead zinc silicate (PbCa3Zn4(SiO4)4) related to beryllonite and trimerite that used to be called calcium larsenite. It was named in honor of Esper F. Larsen Jr. (1879–1961), petrologist of Harvard University.
Esperite has a white, greasy appearance in daylight and is much prized for its brilliant yellow green fluorescence under shortwave ultraviolet light. It is found in association with calcite, franklinite, willemite, hardystonite and clinohedrite. It has also been found as prismatic crystals up to 1 mm in length at the El Dragon Mine, Potosi, Bolivia in association with allophane, chalcomenite, clinochalcomenite and barite.
References
Esperite Wikipedia(Text) CC BY-SA