Brilliant Green Fluorescent Willemite from the Sterling Mine
A red/brown, somewhat rhombohedral, piece of nearly pure willemite, with minor calcite. This red variety of willemite contains manganese and is known as Troostite. Under short wave UV the willemite fluoresces very bright green with lasting phosphorescence, and two small areas of calcite show a typical red response. The specimen shows a similar, but less bright, response under long wave UV. The dimensions of this piece are 45.4 x 41.4 x 19.5 mm, and it weighs 80 grams.
Brilliant green fluorescence under short wave UV (254 nm).
Green phosphorescence/afterglow following exposure to short wave UV (254 nm).
A similar, but less bright response is seen under long wave UV (365 nm).
Same specimen shown under visible light.