fossil

Fossilized Nut / Coprolite / Concretion

Trace Fossil / Permineralized Plant Material

Hardness varies between 3 and 5 on the Mohs scale depending on the mineral replacement (often calcite or silica). Color ranges from light brown to dark brown or grey. Luster is dull to earthy. Structure is organic-mimetic, retaining the shape of a seed or nut.

Identified August 2, 2026More fossil →

Explore Fossilized Nut / Coprolite / Concretion in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed through permineralization or replacement where organic material is slowly substituted by minerals like silica or calcium carbonate in sedimentary environments over millions of years.

Uses & applications

Valued by fossil collectors, used for educational purposes and paleobotanical research.

Geological facts

Specimens like this can sometimes be mistaken for coprolites (fossilized feces) or ordinary ironstone concretions. Fossilized nuts and seeds provide crucial insights into ancient prehistoric ecosystems and flora.

Field identification & locations

Found weathering out of sedimentary rock layers, particularly in river gravels, beaches, and fossiliferous shale formations. Look for distinct botanical shapes and heavier-than-expected weight.

Other fossil specimens

See all

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil

Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

sedimentary

Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

fossil

Fossiliferous Limestone

Limestone with embedded fossil cross-section

sedimentary

Fossiliferous Limestone with Crinoid stems

Limestone (CaCO3) containing Crinoidea fossils

sedimentary