mineral
Chalcopyrite (Peacock Ore)
Copper Iron Sulfide (CuFeS2)
Hardness: 3.5-4 Mohs; Color: Brass yellow to golden; Luster: Metallic; Iridescent tarnish (blue, purple, magenta); Crystal Structure: Tetragonal; Specific Gravity: 4.1-4.3
- Hardness
- 3
- Color
- Brass yellow to golden
- Luster
- Metallic
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Physical properties
Hardness: 3.5-4 Mohs; Color: Brass yellow to golden; Luster: Metallic; Iridescent tarnish (blue, purple, magenta); Crystal Structure: Tetragonal; Specific Gravity: 4.1-4.3
Formation & geological history
Forms primarily in hydrothermal veins, contact metamorphic deposits, and as a magmatic segregation in igneous rocks. Often associated with pyrite, quartz, and fluorite.
Uses & applications
Major ore of copper. Also used as decorative specimens for collectors and in jewelry as 'Peacock Ore' when treated with acid or naturally tarnished.
Geological facts
Often confused with Pyrite but is softer and more yellow. When exposed to air or acid, it develops a vibrant, iridescent oxide layer known as 'Peacock Ore'.
Field identification & locations
Identified by its brassy color, low hardness (scratched by a knife), and typical iridescent tarnish. Found worldwide in major copper mines like those in Montana, Arizona, and Mexico.
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Arenite (SiO2 based)
sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
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Nephrite
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