Esperite is a rare complex calcium

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...

silicate (PbCa₃Zn₄(SiO₄)₄) related to beryllonite and trimerite that used to be called ''calcium larsenite''. Esperite has a white, greasy appearance in daylight and is much prized for its brilliant yellow green

fluorescence Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...

under shortwave

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...

light. It is found in association with calcite,

franklinite Franklinite is an oxide mineral belonging to the normal spinel subgroup's iron (Fe) series, with the formula ZnFe3+2O4. As with another spinel member magnetite, both ferrous (2+) and ferric (3+) iron may be present in Franklinite samples. Di ...

willemite Willemite is a zinc silicate mineral () and a minor ore of zinc. It is highly fluorescent (green) under shortwave ultraviolet light. It occurs in a variety of colors in daylight, in fibrous masses and apple-green gemmy masses. Troostite is a vari ...

hardystonite Hardystonite is a rare calcium zinc silicate mineral first described from the Franklin, New Jersey, U.S. zinc deposits. It often contains lead, which was detrimental to the zinc smelting process, so it was not a useful ore mineral. Like many of t ...

and

clinohedrite Clinohedrite is a rare silicate mineral. Its chemical composition is a hydrous calcium-zinc silicate; CaZn(SiO4)·H2O. It crystallizes in the monoclinic system and typically occurs as veinlets and fracture coatings. It is commonly colorless, wh ...

. 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 Allophane is an amorphous to poorly crystalline hydrous aluminium silicate clay mineraloid. Its chemical formula is Al2O3·(SiO2)1.3-2·(2.5-3)H2O. Since it has short-range atomic order, it is a mineraloid, rather than a mineral, and can be ident ...

, chalcomenite, clinochalcomenite and barite.

References

Mineral galleries
*Pete Dunn, ''Franklin and Sterling Hill, New Jersey: the world's most magnificent mineral deposits'', part 3 p. 368 (1995) *G. Grundmann, et al.: ''The El Dragon Mine, Potosi Bolivia'', Mineralogical Record v.21 #2 p. 142 (1990) *Anthony et al., ''Handbook of Mineralogy'', Vol. 2 (silicates) part 1 p. 225 (1995) Robbins, Manuel: Fluorescence Gems and Minerals under Ultraviolet Light Geoscience Press pp 50–51,243 (1994) Calcium minerals Lead minerals Zinc minerals Nesosilicates Monoclinic minerals Minerals in space group 11 Minerals described in 1928 {{silicate-mineral-stub