Dioptasa
Dioptasa is a mineral with formula CuSiO₃·H₂O, in the Silicatos group. This specimen comes from Sanda Hills, Kimbedi, Mindouli District, Pool, República del Congo and joined the Terrium collection in 2025.
Description
Emerald-green dioptase crystals, very lustrous, translucent, with well-formed faces, lining the interior of a deep cavity. No apparent contacts.
About Dioptasa
Secondary copper mineral, notable for its intense green colour and short prismatic habit. It forms in the oxidation zones of sulphide deposits in arid settings. It can be mistaken for emerald, but dioptase is softer and soluble in acids.
About the locality
Sanda Hills is one of the less common Congolese localities for dioptase, with specimens noted for vivid colour and deep cavities. Production is limited and, unlike better-known deposits such as Renéville or Tsumeb, well-formed pieces from Sanda Hills appear infrequently on the market.
Technical data
- Catalogue No.
- 0039
- Composition
- CuSiO₃·H₂O
- Name
- Dioptasa
- Group
- Silicatos
- Category
- Cavella
- Matrix
- Matriz silícea rojiza
- Mine
- Sanda Hills
- District / Municipality
- Kimbedi
- Province
- Mindouli District
- Region
- Pool
- Country
- República del Congo
- Size (cm)
- 7 x 6 x 4
- Weight
- 91.9 g
- Acquired
- 2025
- Ex-collection
- Francisco M
- Etymology
- The name derives from the Greek "dia" ("through") and "opsis" ("vision"), in reference to its transparency and lustre.
- Quality
- Buena
- Value trend
- Al alza
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