mineral
Mixed mineral specimens, prominently chalcopyrite and amethyst
Chalcopyrite (CuFeS₂) with secondary copper minerals; amethyst, purple quartz (SiO₂)
AI-generated identification · may be incorrectThe left specimen appears brassy, iridescent chalcopyrite with metallic luster and Mohs hardness 3.5–4; the purple specimen is amethyst, vitreous, Mohs 7, with quartz’s trigonal crystal structure. Other pieces may include metallic sulfides and banded or altered host rock; exact identification requires testing.
Identified More mineral →
Explore Mixed mineral specimens, prominently chalcopyrite and amethyst in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
The left specimen appears brassy, iridescent chalcopyrite with metallic luster and Mohs hardness 3.5–4; the purple specimen is amethyst, vitreous, Mohs 7, with quartz’s trigonal crystal structure. Other pieces may include metallic sulfides and banded or altered host rock; exact identification requires testing.
Formation & geological history
Chalcopyrite forms in hydrothermal copper deposits, while amethyst crystallizes in silica-rich volcanic cavities, commonly during the Mesozoic to Cenozoic. The pictured assortment appears to be hand-collected mining specimens rather than one rock.
Uses & applications
Chalcopyrite is an important copper ore; amethyst is used for jewelry, carvings, and mineral collecting. These rough specimens are primarily educational or decorative.
Geological facts
Iridescent chalcopyrite is often sold as “peacock ore,” though the colors usually result from surface oxidation or artificial treatment. Amethyst’s purple color is caused mainly by iron-related defects and irradiation.
Field identification & locations
Identify chalcopyrite by its brassy color, tarnish, metallic streak, and softer hardness than pyrite; amethyst by purple quartz properties and lack of cleavage. Common sources include Mexico, Peru, Brazil, Uruguay, and the western United States.
