Manganiferous Willemite (Var. Troostite), with Franklinite in Calcite – 
Sterling Mine near Ogdensburg, Franklin, New Jersey, USA
 
Manganiferous Willemite (Var. Troostite) as angular pink-brown crystal grains to 4 mm, with shiny black, magnetic Franklinite in Calcite matrix (likewise manganiferous). As it is typical for this worldwide unique zinc deposit within the Franklin marble, the piece shows spectacular fluorescence colours in long- and short-wave UV light: Willemite glows poison-green, the Calcite matrix glows fire-red. After short-wave UV irradiation, the manganiferous Willemite shows a characteristic green phosphorescence. This piece was recovered on a dump in 1967; the potential for finds has been extinguished since the 1970s! Ex Stefan Weiß collection (D.135/1)