sedimentary

Ironstone (with possible Hematite/Limonite coating)

Ironstone (Fe-rich sedimentary rock)

AI-generated identification · may be incorrect

Hardness: 5-6 on Mohs scale; Color: Dark brown, reddish-brown to grey; Luster: Sub-metallic to dull/earthy; Crystal structure: Usually massive or fine-grained; Specific gravity: 3.0-5.0 (relatively heavy)

Hardness: 5-6 on Mohs scale
Color: Dark brown, reddish-brown to grey
Luster: Sub-metallic to dull/earthy

Identified May 12, 2026More sedimentary →

Explore Ironstone (with possible Hematite/Limonite coating) in the encyclopedia →

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Physical properties

Formation & geological history

Formed through the chemical precipitation of iron minerals in sedimentary environments or by the weathering and oxidation of iron-rich rocks. Often found in layered beds or as nodules across various geological ages.

Uses & applications

Primarily used as an ore of iron in the steel industry. Occasionally used in construction (road base) or as a landscaping decorative stone.

Geological facts

Ironstones are the primary source for most of the world\'s iron. The vibrant red or yellow colors seen in such rocks are typically due to the oxidation (rusting) of iron minerals present within the matrix.

Field identification & locations

Identify by its notable weight (heaviness), reddish-brown streak on unglazed porcelain, and common occurrence in old river beds or alongside iron-rich strata.