Chalcopyrite

Chalcopyrite has a golden yellow color, which often resembles Gold. However, its physical properties such as streak and tenacity are very different from Gold and can easily distinguish it. Chalcopyrite is a beautiful mineral, with good crystals being fairly common. It is also readily available, with quality specimens being surprisingly affordable.

"Peacock Ore" which is sold to many amateur mineral collectors often as a variety of Bornite, is in fact almost always Chalcopyrite treated with acid to produce an iridescent tarnish. Though some Chalcopyrite is naturally iridescent, wild colors such as strong blues and purples are usually formed from acid treatment.

Chalcopyrite is a fairly common mineral, and therefore only the finest of localities will be mentioned. Large, well shaped crystals occur in numerous places in Cornwall, England, especially at the Carn Brea area. Baia Sprie (Felsobanya) and Kapnick both in Maramures Co., are famous Romanian occurrences. Very large crystals come from Krushev Dol, in the Rhodope Mountains of Bulgaria. In the Dreislar Mine, North Rhine-Westphalia, Germany, small Chalcopyrite crystals on white coxcomb Barite occur as an excellent combination with beautiful contrast. In China, large crystals occur at the Yaogangxian Mine, Hunan Province.

Many fine Chalcopyrite crystals occur in Zacatecas Mexico; Concepción del Oro and San Martín are noteworthy. The Huaron Mine in Cerro del Pasco, Peru is also a classic locality.

In the U.S., the Tri-state district of Kansas, Oklahoma, and Missouri has provided the important Chalcopyrite localities of Joplin, Jasper Co., Missouri; Picher, Ottawa Co., Oklahoma; and Treece, Cherokee Co., Kansas. The Sweetwater Mine, Reynolds Co., Missouri produces small sparkling crystals, with some having a natural blue iridescence. Other excellent Chalcopyrite occurrences are the Gilman District, Eagle Co., Colorado; Ouray, Ouray Co., Colorado; and Ellenville, Ulster Co., New York. The Chimney Rock Quarry in Bound Brook, Somerset Co., New Jersey, has produced unique reniform blobs; and the the French Creek Mine in Chester Co., Pennsylvania has produced large distorted and highly tarnished crystals that are highly sought after by collectors.