mineral

Polished blue-green metallic mineral specimen, likely bornite (“peacock ore”)

Bornite, Cu₅FeS₄; possibly chalcopyrite, CuFeS₂, with iridescent tarnish

AI-generated identification · may be incorrect

Hardness about 3–3.5 (bornite) or 3.5–4 (chalcopyrite); metallic luster, opaque, blue-green-purple iridescence, and uneven fracture. The visible surface appears polished or naturally weathered rather than showing clear crystal faces.

Identified September 8, 2026More mineral →

Explore Polished blue-green metallic mineral specimen, likely bornite (“peacock ore”) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Polished blue-green metallic mineral specimen, likely bornite (“peacock ore”)
Scientific name: Bornite, Cu₅FeS₄; possibly chalcopyrite, CuFeS₂, with iridescent tarnish
Category: mineral
Identified: September 8, 2026
Method: Standard

AI Estimated Value

About $5–$25 for a small polished/common specimen; $25–$100+ for larger, naturally iridescent or 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

A copper-iron sulfide formed mainly in hydrothermal copper deposits and commonly associated with chalcopyrite, pyrite, and quartz. Such sulfides are generally hydrothermal and may range from Precambrian to younger geological ages.

Uses & applications

Primarily a copper ore and collectible mineral; polished pieces are sold decoratively as “peacock ore.” It is not normally used as a gemstone because of low hardness and susceptibility to tarnishing.

Geological facts

The vivid colors are a thin tarnish layer produced by oxidation, not the inherent color of fresh bornite. Commercial “peacock ore” is often chalcopyrite that has been artificially acid-treated to enhance iridescence.

Field identification & locations

Confirm with a streak, hardness, density, and ideally X-ray diffraction or chemistry; bornite is softer and more copper-rich than chalcopyrite. Common sources include Arizona and Montana (USA), Peru, Mexico, Chile, and Cornwall, England.