The facts
What bornite actually is
Mineralogically, bornite is bornite — Cu₅FeS₄, crystallising in the orthorhombic system.
The colour is caused by fresh surfaces are copper-red to bronze; the blue-purple iridescence is a thin-film oxidation coating that develops within days of exposure. 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 5.06–5.09; cleavage is poor {111}.
Where bornite comes from
The recognised sources are Dzhezkazgan, Kazakhstan, Bristol, Connecticut, USA, Tsumeb, Namibia and Carn Brea, Cornwall, England.
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 bornite is treated
Like chalcopyrite, much retail 'peacock ore' is acid-tarnished to exaggerate the iridescence. The natural film also continues to darken, so specimens change appearance over years. Crystallised bornite is genuinely rare; most material is massive ore.
None of this is a problem when it is said out loud. It becomes one the moment it is left out.
What bornite is confused with
The usual confusions are Chalcopyrite, Covellite, Chalcocite and Acid-treated ore.
Because the material is opaque, refractive index is no help. Specific gravity around 5.06–5.09, hardness of 3, streak and magnification do the work instead.
What bornite is used for
Bornite is bought by mineral collecting, wellness and body care 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 or by the kilo.
Durability and care
Hardness 3; cleavage poor {111}. 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 bornite costs
Indicative pricing for bornite is Tumbled 'peacock ore' $1–$8; crystallised specimens $100–$5,000.
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 bornite treated, and how?
Like chalcopyrite, much retail 'peacock ore' is acid-tarnished to exaggerate the iridescence. The natural film also continues to darken, so specimens change appearance over years. Crystallised bornite is genuinely rare; most material is massive ore.
Where does bornite come from?
Dzhezkazgan, Kazakhstan, Bristol, Connecticut, USA, Tsumeb, Namibia and Carn Brea, Cornwall, England. Origin affects price, so we name the locality rather than the country on every quote.
Is bornite hard enough to wear every day?
Not really. At 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 bornite cost?
Indicatively Tumbled 'peacock ore' $1–$8; crystallised specimens $100–$5,000. 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 bornite confused with?
Most often Chalcopyrite, Covellite, Chalcocite and Acid-treated ore. Since the material is opaque, separation relies on specific gravity near 5.06–5.09, hardness and magnification.
What is bornite used for besides jewellery?
mineral collecting, wellness and body care and metallurgy. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for bornite?
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 bornite