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Cuprite
Current inventory:  1 gem
 

Chemistry:  Cu₂O  [Copper Oxide]

Discovered in 1845;   IMA status: Valid (pre-IMA; Grandfathered).
Cuprite is named after the Latin word cuprum meaning copper due to is chemical content.

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/A.02-10

4 : Oxides & Hydroxides
A : Oxides with metal : oxygen = 1:1 and 2:1 (M2O,MO)
02 : Cuprite series

Crystal Data

Crystallography:

Isometric - Hexoctahedral

Crystal Habit:

As cubic, octahedral, and dodecahedral crystals, to 14 cm, which may be highly modified; as hairlike capillary forms, with square section, reticulated, tufted and matted; also earthy, compact granular, massive.

Twinning:

None

Physical Properties

Cleavage:

[111] Imperfect

Fracture:

Conchoidal to Uneven

Tenacity:

Brittle

Hardness (Mohs):

3.5 - 4.0

Hardness (Vickers):

VHN₁₀₀=183 - 222 kg/mm²

Density:

6.00 - 6.14 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Dark Red, Red, Conchineal Red, Purple Red, sometimes almost Black

Transparency:

Transparent to Translucent

Luster:

Adamantine to Sub-Metallic, Earthy

Refractive Index:

2.849  Isotropic

Birefringence:

0.000  Isotropic

Dispersion:

n/a

Pleochroism:

Sometimes anomalously pleochroic

other:

Anisotropic

Occurances

Geological Setting:

Oxidized zone of copper deposits. Cuprite is commonly found as an oxidation product of copper sulphides in the upper zones of veins.

Type Locality:

n/a

Year Discovered:

1845

View mineral photos:

Cuprite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Cuprite is a very rare and beautiful gem with a very high refractive index, adamantine luster and deep red color. Gem grade crystals mostly come from one location; Onganja, Namibia. Prior to this find, Cuprite gems were almost non-existant. There are a few other locations but crystals are typically very small. Most crystals on the market are obtained by mineral collectors and are not used to cut gems. This makes Cuprite gems even rarer. Cuprite is often associated with Native Copper, Malachite, Azurite, Limonite and Chalcocite. A fibrous form of Cuprite is known as Chalcotrichite.
 

  
Cuprite gems for sale: