Rich violet blue natural D'Block Tanzanite (.82ct, SI1, Africa) hand set in a classy sterling silver ring. Deep violet blue with flashes of red. Tanzanite is a relatively new gemstone in the world of gemology and jewelry, and though its history is brief, it is no less illustrious than many ancient gems. Since its discovery, tanzanite has sold for as little as $20 per carat and as much as $1,000 per carat or more, for gem-quality, finely colored stones. Size 6.5 can be resized up or down 1 size.