Bornite is a copper and iron sulfide mineral with the chemical formula Cu₅FeS₄ . It is valued both for its economic importance in copper extraction and for its spectacular appearance.
🧪 Main features
Name : Bornite
Chemical formula : Cu₅FeS₄
Cool color : coppery brown or bronze
Altered color : iridescent (blue, purple, pink, green...)
Crystal system : orthorhombic (but often pseudocubic)
Hardness (Mohs scale) : 3 to 3.25
Density : 4.9 to 5.3
Luster : metallic
Fracture : unequal to subconchoidal
🌈 Appearance and nickname
When it oxidizes in the air, bornite takes on magnificent iridescent, multicoloured reflections (blue, violet, pink, green). This is why it is often nicknamed " peacock ore".
⛏️ Formation and deposits
Bornite forms in hydrothermal copper deposits, often in association with:
Chalcopyrite
Chalcocite
Pyrite
The covellite
Malachite
It is found in several mining regions around the world, including:
Chile
United States (Arizona, Montana)
Mexico
Peru
Namibia
Canada (British Columbia)
🏭 Usage
Bornite is a source of copper in the mining industry. It contains approximately 63% copper when pure, making it a valuable ore. However, it is less abundant than chalcopyrite.
💎 Collection and scientific interest
Because of its spectacular colors, bornite is highly prized by mineral collectors. It is also studied by geologists to understand hydrothermal processes and copper deposits.
