A Tsumeb dioptase of quality is a capstone in any display collection. "Poor Man's Emerald" as it was once called...ironic, because now that Tsumeb is closed and the best dioptase came out 20 years ago in the 1980s, they are harder to obtain and MORE expensive in many cases than real emeralds. And they only get harder to obtain, and higher priced, every year as we go on from the closure of Tsumeb. I love them, and stash them away for the future myself. This one is among the more elegant and sculptural pieces I have had, with gemmy crystals of highest quality to over 1 cm, perched on an attractive matrix. The matrix is coated with sparkling, drusy calcite for contrast - the best style. I see absolutely no reason save pricing this based on cost and not peak value, that this couldn't equally well be on a shelf at a show for 12-15k. Given the appreciation rate on dioptase and sweet home rhodos, its one of the few mineral species with a really trackable, steady appreciation rate over time which I would even guarantee by offering buyback with profit, down the road. Ex. George Elling Collection