sedimentary

Ironstone Pebble

Sedimentary ironstone / Hematitic Sandstone

Hardness: 5.5-6.5 on Mohs scale. Color: Brown, reddish-brown, tan, and dark gray. Luster: Dull, earthy to slightly metallic on fresh surfaces. Crystal Structure: Fine-grained aggregate composed mainly of quartz and iron oxides (hematite, goethite). Cleavage: None.

Hardness: 5
Color: Brown, reddish-brown, tan, and dark gray
Luster: Dull, earthy to slightly metallic on fresh surfaces

Identified July 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed in sedimentary environments through the deposition of sand grains cemented by precipitating iron oxides from mineral-rich waters. Later weathered and rounded by stream or wave action into a pebble.

Uses & applications

Commonly found in landscaping gravels, stream beds, and gravel deposits. Generally used as construction aggregate or collected as general rock specimens.

Geological facts

Ironstone cobbles and pebbles frequently exhibit a natural brownish-red weather rind due to the oxidation of iron minerals, similar to the rusting of iron metal.

Field identification & locations

Identified by its heavy weight relative to size (high density due to iron content), earthy brown to reddish color, rounded weathered shape, and dull finish. Common along rivers, lakeshores, and glacial drift regions.

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