sedimentary

Ironstone Pebble

Sedimentary Ironstone (Hematite/Limonite-bearing)

AI-generated identification · may be incorrect

Hardness: 5.5-6.5 on Mohs scale; Color: reddish-brown, rusty orange, brownish-tan; Luster: dull to earthy; Crystal structure: microcrystalline to massive; Cleavage: none.

Hardness: 5
Color: reddish-brown, rusty orange, brownish-tan
Luster: dull to earthy

Identified July 25, 2026More sedimentary →

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Physical properties

Hardness: 5.5-6.5 on Mohs scale; Color: reddish-brown, rusty orange, brownish-tan; Luster: dull to earthy; Crystal structure: microcrystalline to massive; Cleavage: none.

Formation & geological history

Formed by the precipitation of iron oxides (such as hematite, limonite, or goethite) within sedimentary layers, often rounded into smooth pebbles by water action in riverbeds or coastal environments.

Uses & applications

Historically used as an ore of iron; small pebbles are commonly used in landscaping, gravel mixes, or as educational specimens for identifying sedimentary iron minerals.

Geological facts

Ironstone gets its distinctive reddish-brown color from weathered iron minerals. It often forms concretions that resist erosion better than surrounding soft rocks.

Field identification & locations

Identified by its heavy feel relative to size, rusty streak, and dull reddish-brown surface. Commonly found along riverbeds, gravel walkways, and in sedimentary rock formations worldwide.