Willemite
Zn2SiO4
Willemite is a silicate mineral prized by collectors for its exceptional color range, with known Chinese sources.
Willemite (Zn₂SiO₄) is a zinc silicate, a minor ore of zinc and a celebrated collector species — above all for its intense green fluorescence under ultraviolet light.
The Franklin connection
The Franklin and Sterling Hill zinc deposit in New Jersey is the classic willemite locality, where it occurs with franklinite and calcite and fluoresces brilliant green (the calcite glows red) — the defining display of fluorescent mineralogy.
What collectors look for
Fluorescent willemite–franklinite–calcite assemblages are the signature; well-crystallised willemite and a strong UV response drive value.