mineral

Bornite (“peacock ore”), likely chalcopyrite-bearing sulfide specimen

Bornite, Cu₅FeS₄, commonly intergrown with chalcopyrite (CuFeS₂) and oxidized copper sulfides

AI-generated identification · may be incorrect

Metallic to submetallic luster; dark bronze-brown fresh surfaces with iridescent purple, blue, green, and gold tarnish. Mohs hardness 3–3.25; opaque, massive, with poor cleavage and high specific gravity (~4.9–5.3).

Identified August 16, 2026More mineral →

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At a glance

Common name: Bornite (“peacock ore”), likely chalcopyrite-bearing sulfide specimen
Scientific name: Bornite, Cu₅FeS₄, commonly intergrown with chalcopyrite (CuFeS₂) and oxidized copper sulfides
Category: mineral
Identified: August 16, 2026
Method: Standard

AI Estimated Value

About $5–$30 for common rough specimens; $30–$150+ for large, vividly iridescent, well-formed pieces.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Forms in hydrothermal copper deposits, commonly replacing or filling veins in igneous and metamorphic host rocks; deposits range from Precambrian to modern geologic ages. The vivid colors develop through surface oxidation and tarnishing.

Uses & applications

Primarily an important copper ore; attractive pieces are sold as mineral specimens and occasionally used decoratively. It is generally unsuitable for jewelry because it is soft and tarnishes readily.

Geological facts

Bornite is nicknamed “peacock ore” for its multicolored oxidation film. Freshly broken bornite is typically copper-brown rather than intensely blue-purple.

Field identification & locations

Identify it by its heavy feel, metallic appearance, softness, and iridescent tarnish; a copper streak or chemical testing can help distinguish it from similarly colored chalcopyrite. Common localities include Cornwall, England; Butte, Montana; Mexico; Peru; and the Canadian Shield.