sedimentary

Ironstone / Hematite Concretion

Iron oxide / Fe2O3

AI-generated identification · may be incorrect

Hardness of 5.5 to 6.5 on the Mohs scale, reddish-brown to dark gray color, metallic to dull earthy luster, amorphous or cryptocrystalline structure, no true cleavage, and a noticeably high specific gravity making it feel heavy for its size.

Identified August 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the precipitation of iron-rich mineral cements in sedimentary environments, often found as nodules or concretions in sandstone or weathered soils over millions of years.

Uses & applications

Primarily collected as a geological specimen, sometimes tumbled or polished for decorative stones or lapidary art.

Geological facts

Ironstone concretions are often weathered out of softer surrounding rock due to their higher resistance to erosion, leading to smooth, rounded, often unusually shaped natural pebbles.

Field identification & locations

Easily identified in the field by its reddish-brown rust color, smooth weathered surface, and notably heavy weight compared to normal quartz pebbles of the same size.