Gemstone profile and identification guide
Dioptase
Dioptase is a bright green copper cyclosilicate mineral prized mainly as a collector crystal and occasional gem.
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Overview
Dioptase is a bright green copper cyclosilicate mineral prized mainly as a collector crystal and occasional gem.
Did you know? Fine dioptase crystals are considered display-quality mineral specimens rather than mainstream jewellery stones.
Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.
Identification
Name: Dioptase
Scientific classification: Silicate (Cyclosilicate: Dioptase)
Hardness: 5 Mohs
Transparency: transparent
Lustre: vitreous
Crystal system: Trigonal
Primary colour: Emerald Green
Secondary colour: Green
Colour family: Greens
Intense emerald-green colour with copper-mineral association and trigonal crystal habit are diagnostic.
Verification Status
Status: verified-core-fields
Reference priority: GIA, Gem-A, Mindat, International Gem Society
Core identity, locality, and physical-property fields reviewed against standard gemological references.
Values are reported as practical gemological ranges where appropriate.
Physical Properties
Hardness category: medium
Hardness value: 5 Mohs
Chemical composition: Hydrated copper cyclosilicate [Cu6Si6O18·6H2O]
Crystal system: Trigonal
Common locations: Namibia, Democratic Republic of the Congo, Kazakhstan, Russia, Chile
Learn more: Gem-A gemstone education resources.
Colour Variations
Vivid emerald-green copper silicate, usually collected as crystals and occasionally cut for gems.
Optical effects: None specified in the current dataset.
Detailed Gemology
Mineral species: Dioptase
Mineral group: Cyclosilicate group
Chemical formula: Hydrated copper cyclosilicate [Cu6Si6O18·6H2O]
Mohs hardness: 5
Crystal system: Trigonal
Lustre: vitreous
Transparency: transparent
Streak: Light green
Cleavage: Perfect in one direction
Fracture: Conchoidal to uneven
Specific gravity: 3.28-3.35
Refractive index: 1.644-1.709
Optical phenomena: None typically diagnostic
Colour range: Emerald green to deep green
Common inclusions: Fractures, growth tubes, limonite and matrix remnants
Geological environment: Oxidized zones of copper deposits
Principal mining regions: Namibia, Democratic Republic of the Congo, Kazakhstan, Russia, Chile
Important commercial sources: Most collector and lapidary-grade dioptase comes from Namibia and the Democratic Republic of the Congo
Historical significance: A classic collector mineral from famous African and Kazakh localities.
Common treatments: Generally untreated; fracture stabilization can occur in cut stones.
Synthetic or imitation forms: Glass and dyed materials can imitate colour.
Common look-alikes: Emerald, chrome diopside, dyed quartz
Jewellery uses: Primarily a collector mineral; limited faceting and protected jewellery use.
Care recommendations: Brittle with cleavage and moderate hardness; handle carefully and avoid ultrasonic cleaning.
Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Dioptase.
Formation
Forms as a secondary mineral in oxidized copper deposits in arid to semi-arid conditions.
Origin
Most collector and lapidary-grade dioptase comes from Namibia and the Democratic Republic of the Congo
Uses
Best for: Primarily a collector mineral; limited faceting and protected jewellery use.
Ideal uses: Collector specimens and occasional faceted stones for careful wear.
Care
Brittle with cleavage and moderate hardness; handle carefully and avoid ultrasonic cleaning.
Need another candidate? Use advanced gemstone search or return to the identification guide.
Related gemstones by colour
Related gemstones by hardness
Commonly confused gemstones
Dioptase FAQ
How can I identify Dioptase?
Compare hardness (5 Mohs), crystal system (Trigonal), colour profile, and lustre (vitreous) with your sample. Then cross-check related gemstones listed above.
What colour range does Dioptase appear in?
Vivid emerald-green copper silicate, usually collected as crystals and occasionally cut for gems.
Where is Dioptase commonly used?
Collector specimens and occasional faceted stones for careful wear.. For maintenance, follow the care guidance in this profile.
Scientific References
GIA: general gemstone identity (reviewed) - Batch 02 factual verification pass.
Gem-A: gemological terminology and testing references (reviewed) - Batch 02 factual verification pass.
Mindat: mineral species and principal localities (reviewed) - Batch 02 factual verification pass.
International Gem Society: gem trade context and treatment overview (reviewed) - Batch 02 factual verification pass.