Esperite is a rare complex calcium lead

Lead

Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...

 zinc

Zinc

Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

 silicate

Silicate minerals

The silicate minerals make up the largest and most important class of rock-forming minerals, constituting approximately 90 percent of the crust of the Earth. They are classified based on the structure of their silicate group...

 (PbCa₃Zn₄(SiO₄)₄) related to beryllonite

Beryllonite

Beryllonite is a rare sodium beryllium phosphate mineral with formula NaBePO4. The tabular to prismatic monoclinic crystals vary from colorless to white or pale yellowish, and are transparent with a vitreous lustre. Twinning is common and occurs in several forms. It exhibits perfect cleavage in one...

 and trimerite that used to be called calcium larsenite. It occurred on the 400 foot level, approximately 1080 feet north of the north side of the Palmer Shaft pillar and other parts of the Franklin, New Jersey ore body.It has a white, greasy appearance in daylight and is much prized for its brilliant yellow green fluorescence

Fluorescence

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

 under shortwave ultraviolet

Ultraviolet

Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 light.