a copper sulfide mineral with the formula Cu5FeS4 containing 63% copper. It was renamed as bornite in 1845 in honor of Ignaz von Born (1742-1791), an Austrian mineralogist. It has a copper-reddish colour on fresh exposure which eventually evolves to black, after exposure to air and moisture. Sometimes bornite is nicknamed ‘peacock ore’ due to its colorful appearance by oxidation.