The facts
What cuprite actually is
Mineralogically, cuprite is cuprite — Cu₂O, crystallising in the cubic system.
The colour is caused by cu⁺ oxide with a band gap in the green, giving deep crimson transmitted colour. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer reads 2.848, and the specific gravity sits near 5.8–6.2; cleavage is poor octahedral {111}.
Where cuprite comes from
The recognised sources are Onganja Mine, Seeis, Namibia, Rubtsovskoye, Altai Krai, Russia, Bisbee, Arizona, USA and Chessy-les-Mines, Rhône, France.
Origin affects price in this material, so we name the locality on every quote rather than the country. "African" or "Asian" tells a buyer nothing.
How cuprite is treated
Untreated, but cuprite darkens and dulls on long light exposure as the surface converts to tenorite; display specimens should be kept out of sunlight. The 1970s Onganja gem crystals remain the only significant source of facetable material.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What cuprite is confused with
The usual confusions are Ruby, Almandine garnet, Zincite, Realgar and Proustite.
The separation is rarely a matter of opinion: refractive index 2.848 and specific gravity 5.8–6.2 settle most of it in a minute, and magnification settles the rest.
What cuprite is used for
Cuprite is bought by mineral collecting and jewellery — and each of those trades wants a different form of the same material.
We quote each application in the unit that trade actually buys in, by the specimen or by the carat.
Durability and care
Cuprite is 3.5–4 on the Mohs scale, with poor octahedral {111} cleavage.
Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What cuprite costs
Indicative pricing for cuprite is Onganja faceted stones $300–$2,000/ct; crystal specimens $50–$10,000.
That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.
Questions
Is cuprite treated, and how?
Untreated, but cuprite darkens and dulls on long light exposure as the surface converts to tenorite; display specimens should be kept out of sunlight. The 1970s Onganja gem crystals remain the only significant source of facetable material.
Where does cuprite come from?
Onganja Mine, Seeis, Namibia, Rubtsovskoye, Altai Krai, Russia, Bisbee, Arizona, USA and Chessy-les-Mines, Rhône, France. Origin affects price, so we name the locality rather than the country on every quote.
Is cuprite hard enough to wear every day?
Not really. At 3.5–4 on the Mohs scale it is softer than the quartz dust in ordinary household dirt, so it scratches with wear. It suits pendants, earrings and objects better than a daily ring.
How much does cuprite cost?
Indicatively Onganja faceted stones $300–$2,000/ct; crystal specimens $50–$10,000. Colour, size, clarity and origin move the price a long way within that, so treat it as a range and ask for a quote against a specific stone.
What is cuprite confused with?
Most often Ruby, Almandine garnet, Zincite, Realgar and Proustite. A refractive index of 2.848 and a specific gravity near 5.8–6.2 separate it quickly.
Related stones
Looking for cuprite?
Tell us the size, the quality and what it is for. We source it, photograph it and quote it — with the locality named.
Ask about cuprite