Sphalerite & Wurztite 2016 01
Sphalerite from Spain
&
Wurtzite from Tanzania
Cousins. Left, sphalerite from Spain, 11.34 ct., 12.8 x 12.8 x 8.5 mm. Right, rare wurtzite from Mahenge, Tanzania, 5.81 ct., 12.4 x 8.3 x 6.2 mm. Both of these stones were custom cut by Brett Kosnar. Prices available upon request. (Photo: Mia Dixon)
This duo has similar upbringings but very different features. Born of zinc and sulfur, these two minerals could make great ore for extracting zinc, but in this case they crystallized into fine specimens.
Sphalerite is a low-temperature polymorph of ZnS while wurtzite is the high-temperature polymorph. Beyond the technical relationship lie two very different jewels. The sphalerite is a bright and happy yellow hue with high dispersion and scintillation. The wurtzite on the other hand has a dark and intense ruby-like hue with an unusual metallic sheen. These are great collectable gems with varying beauty and cool optical properties.