noun
- Plural of dioptase; a rare copper silicate mineral that typically forms bright blue-green crystals.
Usage: mineralogy; technical
Examples
- Dioptases are prized by mineral collectors for their vivid emerald-green color.
- The museum's geology exhibit featured several specimens of dioptases from Kazakhstan.
- Dioptases form in the oxidized zones of copper ore deposits.
- Collectors often seek out well-formed dioptases for their crystal clarity and hue.