Where is Peacock Ore (when tarnished) found?
CuFeS2 (Chalcopyrite) and Cu5FeS4 (Bornite)
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Open the appPeacock Ore (when tarnished) occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Peacock Ore (when tarnished)
Bingham Canyon Mine, Utah, USA
One of the largest open-pit mines in the world, a classic porphyry copper deposit with abundant chalcopyrite and bornite.
Butte, Montana, USA
Historically significant copper mining district, known for its rich vein deposits containing chalcopyrite and bornite.
Cornwall, England
Historic mining region with numerous copper-tin lodes, where chalcopyrite and bornite are common.
Kupferschiefer deposits, Poland/Germany
World-class sedimentary copper deposits where bornite and chalcopyrite are major ore minerals.
Chuquicamata, Chile
Another massive porphyry copper deposit, rich in chalcopyrite and bornite.
Collecting tips
- Look for Metallic Luster. Both minerals exhibit a distinct metallic luster, even when tarnished. This is a key indicator for sulfide minerals.
- Observe Color and Tarnish. The brassy yellow of chalcopyrite and the rapid, iridescent tarnish of bornite are highly diagnostic. Freshly broken bornite will show a reddish-brown color before tarnishing.
- Check for Associated Minerals. These minerals often occur with other sulfides like pyrite, sphalerite, and galena, as well as quartz, calcite, and various silicates in their host rocks.
- Consider Geological Context. Focus on areas known for copper mineralization, such as hydrothermal alteration zones, porphyry intrusions, or VMS deposits.
- Hardness Test. Chalcopyrite (3.5-4) and Bornite (3) are relatively soft and can be scratched by a steel knife, distinguishing them from harder minerals like pyrite (6-6.5).
Quick Check
- Color:
- Chalcopyrite: Brassy yellow, often tarnished iridescent. Bornite: Reddish-brown (fresh), rapidly tarnishing to iridescent blue, purple, red.
- Luster:
- Metallic.
- Streak:
- Chalcopyrite: Greenish-black. Bornite: Grayish-black.
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