Gem topaz from the Schneckenstein crag, Saxony, Germany: Mineralogical characterization and luminescence

Yellow topaz from the Schneckenstein crag in Saxony, Germany, is a famous and historically important gemstone. Surprisingly, mineralogical studies of the material are comparably scarce and have focused mainly on crystal forms and trace element geochemistry. The present study provides a mineral-chemical and spectroscopic characterization of Schneckenstein topaz and its inclusions taking into consideration past and current research results. Particular emphasis lies on the photoluminescence (PL) behavior of the material. Schneckenstein topaz appears inert under common long-wave (~365 nm) and short-wave (~254 nm) UV light sources. In contrast, excitation wavelengths in the 400–440 nm range are much more efficient in exciting pinkish red emission that is assigned to trace levels (10–40 ppm) of Cr3+ incorporated at the six-coordinated Al3+ site.