The facts
What copper actually is
Mineralogically, copper is copper (native element) — Cu, crystallising in the cubic system.
The colour is caused by metallic reflectance with an interband absorption edge in the blue-green giving the reddish colour. That is worth knowing because it determines what heating, light and time can and cannot do to the stone.
A refractometer gives nothing, because the material is opaque, and the specific gravity sits near 8.9; cleavage is none; very malleable.
Where copper comes from
The recognised sources are Keweenaw Peninsula, Michigan, USA, Ray Mine, Arizona, USA, Rubtsovskoye, Altai, Russia and Tsumeb, Namibia.
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 copper is treated
Almost all display specimens are chemically cleaned and then waxed or lacquered; some Michigan crystals are re-attached to matrix. Cast reproductions exist.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What copper is confused with
The usual confusions are Cuprite with copper coating and Tarnished bronze casts.
Because the material is opaque, refractive index is no help. Specific gravity around 8.9, hardness of 2.5–3, streak and magnification do the work instead.
What copper is used for
Copper is bought by mineral collecting, decorative objects, technical and precision components, heavy industry and metallurgy — 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, by the piece or by the tonne.
Durability and care
Hardness 2.5–3; cleavage none; very malleable. That combination decides what it can safely be set into.
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 copper costs
Indicative pricing for copper is Cabinet crystallised specimens $100–$5,000; float copper masses sold by weight.
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 copper treated, and how?
Almost all display specimens are chemically cleaned and then waxed or lacquered; some Michigan crystals are re-attached to matrix. Cast reproductions exist.
Where does copper come from?
Keweenaw Peninsula, Michigan, USA, Ray Mine, Arizona, USA, Rubtsovskoye, Altai, Russia and Tsumeb, Namibia. Origin affects price, so we name the locality rather than the country on every quote.
Is copper hard enough to wear every day?
Not really. At 2.5–3 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 copper cost?
Indicatively Cabinet crystallised specimens $100–$5,000; float copper masses sold by weight. 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 copper confused with?
Most often Cuprite with copper coating and Tarnished bronze casts. Since the material is opaque, separation relies on specific gravity near 8.9, hardness and magnification.
What is copper used for besides jewellery?
mineral collecting, decorative objects, technical and precision components, heavy industry and metallurgy. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for copper?
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 copper