Rare Faceted Wurtzite
Raman spectroscopy and X-ray powder diffraction conclusively identified the stone as wurtzite. EDXRF analysis detected zinc and sulfur, which further supported this identification.
Wurtzite, a polymorph of sphalerite, commonly occurs in hydrothermal vein deposits associated with barite and sphalerite. Facet-grade wurtzite has been reported to occur in Merelani, Tanzania (Winter 2013 GNI, p. 261). This is the first wurtzite examined by the GIA laboratory.