sedimentary

Bog Iron

Limonite / Goethite aggregate

AI-generated identification · may be incorrect

Hardness 4-5.5 on the Mohs scale, reddish-brown to dark brown color, dull to submetallic luster, amorphous to microcrystalline structure with typical vesicular or porous texture.

Identified October 18, 2026More sedimentary →

Explore Bog Iron in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness 4-5.5 on the Mohs scale, reddish-brown to dark brown color, dull to submetallic luster, amorphous to microcrystalline structure with typical vesicular or porous texture.

Formation & geological history

Formed in acidic wetlands, bogs, and shallow lakes through the chemical or biochemical oxidation of iron carried in solution by groundwater.

Uses & applications

Historically used as an ore for smelting iron; currently collected as an educational or geological specimen.

Geological facts

Bog iron was the primary source of iron for early European settlers in eastern North America and was utilized by various indigenous cultures.

Field identification & locations

Easily identified by its high density, dark brown rust color, and pitted, vesicular appearance. Frequently found in glaciated regions with abundant ancient wetlands, highly plausible for the reported coordinates in southeastern Wisconsin.