mineral

Tumbled metallic sulfide specimen, likely chalcopyrite

Chalcopyrite (CuFeS₂), possibly polished or coated

AI-generated identification · may be incorrect

Brassy yellow to bronze metallic luster with dark tarnish and rounded tumbled surfaces; Mohs hardness 3.5–4, tetragonal crystal system, indistinct cleavage, specific gravity about 4.1–4.3. The bluish-purple iridescence is typical of tarnished or artificially treated chalcopyrite (“peacock ore”).

Identified August 21, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in hydrothermal copper deposits, commonly with pyrite, sphalerite, and galena; most specimens formed during ancient ore-forming events ranging from Precambrian to younger geological ages. A polished/tumbled piece has been mechanically shaped after collection.

Uses & applications

Used primarily as a copper ore and sold as an inexpensive collector or décor specimen; attractive iridescent pieces are sometimes used in jewelry, though they are relatively soft and easily scratched.

Geological facts

Peacock ore is usually chalcopyrite whose surface has oxidized naturally or been treated to enhance rainbow colors; vivid uniform coloration may indicate treatment.

Field identification & locations

Identify by its unusually dense feel, metallic brass color, and blue-purple tarnish; it is softer than quartz and may leave a dark streak. Common localities include Peru, Mexico, the United States, Canada, and Kazakhstan.