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Ultra rare Spanish Sphalerite. This material has extremely high dispersion, more so than diamond. One of the few known gems that compares to the luster of diamond. Rarely found facet grade with Santander Spain, the area known for most of the worlds finest Sphalerite gems. Unfortunately, little to no mining occurs any more, as the mines have flooded and caved in. Due to its softness (hardness of 4) it is best as a collectors stone or set into pendants. This material was mined over 20 years ago.