sedimentary

Weathered, pyrite-bearing shale

Clay-rich shale, possibly containing pyrite (FeS₂) and quartz

AI-generated identification · may be incorrect

Gray-brown, fine-grained, dull and fissile, with scattered brassy or silvery reflective grains. Shale is generally soft (about 2–3 Mohs); pyrite is harder (6–6.5 Mohs) and metallic-lustrous. The image alone cannot confirm the reflective mineral.

Identified October 15, 2026More sedimentary →

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Physical properties

Formation & geological history

Shale forms as mud and clay settle in quiet water and become compacted and cemented; pyrite can form in oxygen-poor sediments. Its age and exact depositional setting cannot be determined from the photograph.

Uses & applications

Common shale is used for brick, cement, and aggregate; pyrite-bearing pieces are mainly of geological or collector interest.

Geological facts

Pyrite is often called fool’s gold, but its crystals are commonly cubic. Weathering of pyrite may produce acidic runoff.

Field identification & locations

Look for thin layering and easy splitting; pyrite is brassy and brittle, while mica flakes are often brighter and peel into sheets. Shale occurs in sedimentary basins worldwide.