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Cuprite
Current inventory:  0 gems
 

Cuprite

  
Cuprite was named in 1845 by Wilhelm Karl von Haidinger from the Latin word
cuprum, meaning copper, in allusion to its composition. Haidinger renamed a previously known mineral that had been known by a wide variety of names.

Possibly discovered as early as 1546; IMA status: Valid (pre-IMA; Grandfathered)

 

Chemistry

 

 

Chemical Formula:

Cu2O

 

Copper Oxide

Molecular Weight:

143.09 gm

Composition:

Copper

88.82 %

Cu

100.00 %

Cu2O

 

Oxygen

11.18 %

O

 

 

 

 

100.00 %

 

100.00 %

= TOTAL OXIDE

 

 

Classification

   

   

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/A.02-10

Nickel-Strunz 10th Ed. ID:

4.AA.10

 

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
A : Metal: Oxygen = 2:1 and 1:1
A : Cation:Anion (M:O) = 2:1 (and 1.8:1)

Related to:

n/a

Varieties:

Chalcotrichite, Tile ore

Synonyms:

ICSD 63281, Hepatinerz (of Breithaupt), Kupferglas, Octahedral Copper, Octahedral Copper Ore, Oxydulated Copper, PDF 5-667, Red Copper, Red Glassy Copper Ore, Red oxide of Copper, Ruberite, Ruby Copper 

 

 

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:

Penetration twins common

 

 

Physical Properties

   

 

Cleavage:

Interrupted on {111}, more rarely on {001}

Fracture:

Conchoidal, irregular/uneven

Tenacity:

Brittle

Moh's Hardness:

3.5 - 4.0; Vickers: VHN100=183 - 222 kg/mm2  

Density:

6.14 g/cm3 (measured)

Luminescence:

None

Radioactivity:

Not Radioactive

 

 

Optical Properties

   

   

Color:

Cochineal-red, ruby-red, purplish red, to nearly black; in transmitted light, cochineal-red or red in thick sections; yellow-orange, yellow, lemon-yellow in progressively thinner sections; in reflected light, gray blue, commonly with many red internal reflections

Transparency:

Transparent to translucent

Luster:

Adamantine to submetallic, earthy

Refractive Index:

2.849  Isotropic

Birefringence:

0.000 (Isotropic)

Dispersion:

n/a

Pleochroism:

Anomalous, common

Anisotropism:

Anomalously anisotropic. Color in reflected light: bluish white. Internal reflections: blood-red.

 

 

Occurances

   

   

Geological Setting:

A common mineral in the oxidized portions of many copper deposits.

Common Associations:

Copper, Tenorite, Malachite, Azurite, Calcite, Brochantite, Antlerite, Atacamite, Chrysocolla, iron oxides, clay minerals

Common Impurities:

n/a

Type Locality:

Unknown

Year Discovered:

Possibly discovered as early as 1546.

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 mine, 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 from Onganja are obtained by mineral collectors and are not used to cut gems. This makes Cuprite gems even rarer.

Cuprite is commonly found as an oxidation product of copper sulphides in the upper zones of veins and often associated with Azurite, Chalcocite, Native Copper, Limonite and Malachite. A fibrous form of Cuprite is known as Chalcotrichite. Cuprite crystals and gems may be so dark red as to look almost black but when properly lit can show a truely amazing ruby or blood red color.

Cuprite was named in 1845 by Wilhelm Karl von Haidinger from the Latin word cuprum, meaning copper, in allusion to its composition. Haidinger renamed a previously known mineral that had been known by a wide variety of names. The earliest reference to Cuprite may have been in 1546 by the German name Lebererzkupfer, meaning liver ore copper. Other previous names were: Hepatinerz (of Breithaupt), Kupferglas, Ruberite, Ruby Copper and Ziegelerz.

Cuprite distribution: A few localities for fine specimens include: at Bogoslovsk, Nizhni Tagil, and Yekaterinburg (Sverdlovsk), Ural Mountains, Russia. At Dzhezkazgan, Kazakhstan. In England, fine crystals from many mines in Cornwall. At Rheinbreitbach, North Rhine-Westphalia, Germany. In Namibia, large crystals from the Onganja mine, 60 km northeast of Windhoek, and at Tsumeb. At Likasi, Ruwe, and the Mashamba West mine, Kolwezi, Katanga Province, Congo (Shaba Province, Zaire). In the USA, in Arizona, large crystals from Bisbee, Cochise County, at Ray, Pinal County, Globe, Gila County, and elsewhere; from Santa Rita, Grant County, New Mexico. From Boleo, Baja California, Mexico. At Chuquicamata, Antofagasta, Chile. In Australia, from Broken Hill and Cobar, New South Wales; at Burra-Burra and Moonta, South Australia; large crystals in the Red Dome mine, Chilliago, Queensland.
 

  
Cuprite gems for sale:

Cuprite-001

Gem:

Cuprite

Stock #:

CUPR-001

Weight:

12.1380 ct

Size:

13.23 x 8.99 x 6.73 mm

Shape:

Cut-corner rectangle

Color:

Dark Red

Clarity:

Eye Clean

Origin:

Onganja, Namibia

Treatment:

None (natural)

Price:

SOLD (but we have others)

Pictures are of the actual gem offered for sale.
Gem images are magnified to show detail.

Cuprite-001

An extremely rare and large gem from Onganja Mine, Onganja, Seeis, Windhoek District, Khomas Region, Namibia. Cuprite is very difficult to photograph. The first picture is with normal, diffused lighting, the second picture is with strong, direct lighting.


 


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