mineral

Pyrite in Matrix with Copper Alterations

Iron Sulfide (FeS2) with secondary Copper carbonates/sulfides

AI-generated identification · may be incorrect

Hardness: 6-6.5 (for pyrite); Color: Brass-yellow with green/blue surface staining; Luster: Metallic; Crystal Structure: Isometric (cubic/pyritohedral); Cleavage: Indistinct; SG: 4.8-5.0

Hardness: 6-6
Color: Brass-yellow with green/blue surface staining
Luster: Metallic

Identified July 14, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (for pyrite); Color: Brass-yellow with green/blue surface staining; Luster: Metallic; Crystal Structure: Isometric (cubic/pyritohedral); Cleavage: Indistinct; SG: 4.8-5.0

Formation & geological history

Formed in hydrothermal veins through precipitation of iron-rich fluids, often associated with copper mineralization. The greenish hues indicate surface oxidation to minerals like malachite or chalcopyrite alterations.

Uses & applications

Primarily a source of sulfur and iron in industry; widely used as a decorative specimen and in early firearms as a spark source (wheellock pistols).

Geological facts

Commonly known as Fool's Gold, pyrite can produce sparks when struck against steel. Massive pyrite deposits are a significant indicator of nearby base metal deposits like copper and gold.

Field identification & locations

Identify by its metallic brass color and greenish oxidation signs. Found in mining districts globally, particularly in Spain, Peru, and the USA. Collectors look for the contrast between the metallic luster and the colorful oxidation.