Willemite Var. Troostite – Sterling Mine, Franklin, New Jersey, USA
 Ex Collection A. Otto
 Ex Collection Dr. Lechner, Vienna
 Via Anton Berger Vienna
 Ex Collection Exchange
 Via Christian Weise, 1978

 Historical hand specimen with complete documentation!
 A manganese-rich variety of willemite from the zinc mines of the Franklin District in New Jersey.
 Sharp and geometric crystals of willemite, like those seen here, are rarer than the typical grains found in specimens from Franklin, New Jersey, embedded in calcite, franklinite, and zincite. The largest crystal on this piece measures a remarkable 2.5 cm. As is typical of Franklin minerals, the troostite crystals fluoresce bright green under short-wave UV light, creating a beautiful contrast with the calcite in which they are embedded.
 The possibility of finding them has been lost since the 1970s!