Chalcopyrite
Image: Adrian Tync (CC BY-SA 4.0)
Mineral NameChalcopyrite
Chemical FormulaCuFeS2
Mohs Hardness3.5
Crystal Systemtetragonal
Lustermetallic
Streak Colorgreenish-black
Cleavagepoor/indistinct on {011}
Fractureuneven
Specific Gravity4.1
Colorsbrassy yellow, golden yellow, iridescent blue, purple, red
Transparencyopaque
Type LocalityLubin, Poland
Mineral GroupSulfides
Usesprimary ore of copper, collector's specimens
Associated Mineralsbornite, pyrite, sphalerite, galena, quartz
Raritycommon
Description
This specimen displays brassy yellow chalcopyrite, partially covered by a vibrant iridescent tarnish of blues, purples, and reds, often referred to as 'peacock ore', alongside darker, more purplish bornite.
Geological Context
Chalcopyrite is a widespread copper iron sulfide mineral found in various ore deposits, including hydrothermal veins, porphyry copper deposits, and volcanogenic massive sulfide (VMS) deposits, forming under reducing conditions.
