mineral

Pyrite (likely iron pyrite)

Pyrite, FeS₂; possibly a small gold-bearing sulfide specimen

AI-generated identification · may be incorrect

Brassy yellow metallic luster with dark tarnish and angular crystal faces; Mohs hardness 6–6.5, cubic crystal system, poor cleavage, and specific gravity about 5.0. The specimen appears irregular or partially crystallized rather than a perfect cube.

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Pyrite forms when iron and sulfur combine in low-oxygen hydrothermal veins, sedimentary rocks, and metamorphic environments; deposits range from ancient Precambrian rocks to modern geological settings. It commonly crystallizes in cavities and sulfide-rich ore bodies.

Uses & applications

Used industrially as a sulfur source and historically for sulfuric-acid production; attractive crystals are sold as collector specimens and occasionally used in jewelry, though they can tarnish or oxidize.

Geological facts

Its metallic gold-like color gives rise to the nickname “fool’s gold,” but pyrite is harder and more brittle than gold. Striking pyrite can produce sparks and a sulfurous odor if aggressively fractured.

Field identification & locations

Identify it by its brassy metallic color, high density, brittleness, and lack of gold’s malleability; a streak test gives a greenish-black to brown-black streak, unlike gold’s yellow streak. Common localities include Spain, Peru, China, Italy, the United States, and Canada.