mineral

Metallic sulfide ore, likely pyrite-bearing rock

Pyrite (FeS₂), possibly with marcasite or other sulfides

AI-generated identification · may be incorrect

Dark gray to brassy metallic luster with granular, irregular texture; pyrite hardness 6–6.5 Mohs, cubic crystal system, poor cleavage, and specific gravity about 5.0. The specimen appears massive rather than showing distinct cubic crystals, so exact identification from the image is uncertain.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms in hydrothermal veins and sedimentary environments by precipitation from sulfur-rich, iron-bearing fluids; deposits range from ancient Precambrian to geologically young. Its porous, metallic appearance may also indicate an ore fragment or weathered sulfide-rich material.

Uses & applications

Pyrite is mined for sulfur and historically for sulfuric-acid production, though it has limited modern use; attractive crystals are collected and occasionally used decoratively. It is generally not a jewelry gemstone because it tarnishes and can oxidize.

Geological facts

Often called “fool’s gold,” pyrite is harder and more brittle than gold and commonly produces a dark streak, unlike gold’s yellow streak. Sulfide specimens can generate acidic drainage when exposed to air and moisture.

Field identification & locations

Look for a metallic brassy color, high density, and a dark greenish-black streak; a streak test and hardness test are more reliable than color. Common sources include Spain, Peru, Italy, China, and many sulfide-ore districts worldwide.