Mineral · Cyclosilicates
Dioptase
Cu6Si6O18·6H2O
Dioptase is emerald-green hydrated copper silicate, found as short prismatic crystals at Tsumeb (Namibia), Renéville and Mindouli (Congo) and Altyn-Tyube (Kazakhstan). Tsumeb dioptase on calcite is the classic specimen; Congolese dioptase is more affordable. Its vivid green is unmistakable, but its perfect cleavage makes it fragile.
| Formula | Cu6Si6O18·6H2O |
|---|---|
| IMA status | grandfathered |
| Crystal system | Trigonal |
| Mohs hardness | 5 |
| Group | Cyclosilicates |
| Type locality | Altyn-Tyube, Kazakhstan |
| Streak | Pale green |
| Specific gravity | 3.3 |
| Reference list | IMA List of Minerals (RRUFF) — verify formula and status against the current list |
Elsewhere
Cite this article
Stratum Study. "Dioptase" (Mineral). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/minerals/dioptase. Accessed 2026-09-20.
@misc{stratum-dioptase,
title = {Dioptase},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/minerals/dioptase}},
year = {2026},
note = {Mineral article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, wikidata, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.