Picos de Europa, SpainFrom a very small mine, now closed for at least twenty years, comes this superb and rare faceted sphalerite. Sphalerite, a zinc iron sulfide, usually found in black and very occasionally in the pleasant orange color seen here—it is rarely seen cut into a gemstone. The luster of sphalerite is its strongest attribute, i.e. it is adamantine, with a high refractive index and brilliance greater than diamonds. Burnt umber to orange flashes abound in this spectacular octagonal-shaped stone with excellent clarity and luster. The precision cutting provides excellent scintillation to the stone. Of particularly large carats size for the species, which originates from the classic source in Spain, this offering is worthy of display in a museum setting. Weighing approximately 166.33 carats and measuring 32.68 x 22.55mm