Dioptase crystals to 1.5cm of top color saturation and top luster dominate this small cabinet specimen! It is a top-shelf Dioptase of a caliber that most of us will never see in person, and they get more rare and expensive every year. Tsumeb is gone for good, and these stand as one of the great mineral finds of the 20th Century. There are many NICE Dioptase specimens out there, but very few EXCELLENT pieces like this one that are available. Crystals are an intense emerald green with fiery bright green internal reflections and super high luster! Crystal size is definitely bimodal with a smaller, slightly earlier generation of crystals that are between 0.5 to 3mm that are bright and gemmy, largely owing to their small size and the high contrast white Calcite for a background. The larger crystals from about 1 to 1.5cm in size are just slightly later in the paragenesis and are a very saturated emerald green. Both sizes with their unique color characteristics and variation from isolated crystals to ideal an clustering that highlights their sharp crystal form, provide great visual appeal especial on the dazzling white Calcite. The Calcite is very nice too in that aside from affording an ideal background color are of nice size, varying between 2 and 7mm, which is of unusually large size. The best Dioptase specimens from Tsumeb (circa early 1980s) are generally considered to be those perched upon color-contrasting, white Calcite, as here. There is no damage to any of the crystals on the display face save one area on the lower right where a crystal may be missing but isn't noticeable. Minor contacting at the periphery at the left, right and bottom out of sight, and only a trace of micro-chatter on the edge of two crystals. None of this detracts from this exceptional piece that is well-trimmed, a great size and balance, and has phenomenal color.