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Dioptase identification and geology

Dioptase mineral reference specimen

Hydrated copper silicate with intense emerald-green color. Too soft and brittle for jewelry but prized by collectors. Color: Intense emerald green. Luster: Vitreous. Streak: Pale greenish-blue. Cleavage: Perfect in three directions. Hardness: 5. Transparency: Transparent to translucent. Crystal system: Hexagonal Trigonal. Chemical formula: CuSiO₃·H₂O. Specific gravity: 3.28-3.35. Formation: Forms in the oxidized zone of copper deposits in arid environments by reaction of silica-rich solutions with copper. Common geological settings: Namibia Tsumeb , Kazakhstan, Democratic Republic of Congo, USA; found in oxidized copper deposits. Common look-alikes and related entries: Emerald, Malachite, Brochantite.

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  • Malachite

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T14:37:11.710833+00:00
Review status
Published; not independently peer-reviewed
  • IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
  • Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.

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Common questions

What is Dioptase?
Hydrated copper silicate with intense emerald-green color. Too soft and brittle for jewelry but prized by collectors.
How can you identify Dioptase?
Compare several properties rather than relying on colour alone. This entry records colour: Intense emerald green; lustre: Vitreous; streak: Pale greenish-blue; Mohs hardness: 5; cleavage: Perfect in three directions; crystal system: Hexagonal Trigonal; transparency: Transparent to translucent. Confirm an important identification with additional field tests or qualified laboratory work.
How does Dioptase form?
Forms in the oxidized zone of copper deposits in arid environments by reaction of silica-rich solutions with copper.
Where is Dioptase commonly found?
Namibia Tsumeb , Kazakhstan, Democratic Republic of Congo, USA; found in oxidized copper deposits.
What is Dioptase commonly confused with?
Dioptase may be confused with Emerald, Malachite, Brochantite. Compare multiple diagnostic properties because colour and surface appearance can overlap.

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