DIOPTASE

This is an eye-catching cluster of high-quality, gemmy dioptase, perched exquisitely on a quartz matrix, from the type locality for the species. The largest crystal measures to almost an inch, large for the species in general, and stands out even more from Altyn-Tyube. Under strong light, the main crystal shows flashes of emerald fire from the inside, and strong luster on the outside. The main crystal here is absolutely pristine as well. Any blemishes are indistinguishable when viewing it on display, and this is a gorgeous arrangement all around. Though it looks nice already, with careful trimming it could be an even better miniature or thumbnail.     More info: The dioptase occurrence at Altyn-Tyube, Kazakhstan, represents a significant type locality for understanding copper silicate mineralization in oxidized zones. The formation involves hydrothermal alteration of copper sulfides, where Cu6Si6O18·6H2O precipitates under supergene conditions below 100°C. The process requires specifi