sedimentary

Coprolite

Fossilized Feces

Hardness: 3.5-6.5 on Mohs scale; Color: typically brown, tan, or black; Luster: earthy to dull; Structure: often retains the shape of the digestive tract; Chemical composition: often replaced by calcium phosphate (apatite), silicates, or iron oxides.

Hardness: 3
Color: typically brown, tan, or black
Luster: earthy to dull

Identified June 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed by the mineralization of animal waste over millions of years. This process typically occurs in anaerobic environments where the waste is buried quickly by sediment, allowing minerals to replace organic matter. They range from the Paleozoic to the Cenozoic eras.

Uses & applications

Primarily used for scientific research to understand ancient diets and ecosystems. Also used as a curiosity for collectors and sometimes polished for unique jewelry pieces.

Geological facts

The largest coprolite ever found is named 'Barnum' and measures over 2 feet long. Coprolites can contain fossilized remains of the animal's last meal, such as bone fragments, fish scales, or plant material.

Field identification & locations

Identify in the field by looking for 'pinch' marks, a spiral shape, or inclusions of undigested matter. They are commonly found in fossil-bearing sedimentary formations where other vertebrate fossils appear. Collectors should check for high phosphate content using acid tests.