Very common mineral belonging to the sulfide class.
Chalcopyrite is a very important copper ore.
Chalcopyrite from Peru
The black matrix is either schist or steatite.
Origin of name: from greek chalkos copper and pyros fire
Synonyms and trade names: yellow copper, fool´s gold, Apache gold.
Note: the names fool´s gold and Apache gold are also applied to pyrite.
Can be confused with: pyrite agate. Pure chalcopyrite (without matrix) can easily be confused with pyrite. However, chalcopyrite sports a darker, mostly very slightly greenish yellow.
Localities: very common. Mindat lists more than 20.000 deposits the world over. There are even two deposits in Greenland.
For jewellery mostly the matrix variety is used. Important sources for this material are in Peru and in Arizona, USA.
Handling: chalcopyrite is rather soft, brittle and susceptible to acids and heat.
Worth knowing: chalcopyrite produces a characteristic greenish black streak. Upon oxidation chalcopyrite tarnishes to bright iridescent colours. This material is sometimes called "peacock copper (ore)". Chalcopyrite turns magnetic when heated.