Rock Identifier
Calamites (Fossil Horsetail) (Calamites sp. (Internal pith cast)) — fossil
fossil

Calamites (Fossil Horsetail)

Calamites sp. (Internal pith cast)

AI-generated identification · may be incorrect

Hardness 6-7 (typically preserved in sandstone or siltstone), dull earthy luster, ribbed columnar structure with distinct longitudinal ridges and joint nodes.

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Physical properties

Hardness 6-7 (typically preserved in sandstone or siltstone), dull earthy luster, ribbed columnar structure with distinct longitudinal ridges and joint nodes.

Formation & geological history

Formed during the Carboniferous period (approx. 360-300 million years ago) via sediment casting the hollow pith cavity of extinct tree-sized horsetails in swamp environments.

Uses & applications

Prized as educational and display specimens for fossil collectors and paleontological study.

Geological facts

Calamites could grow over 30 to 50 feet tall and were major contributors to the formation of modern coal deposits.

Field identification & locations

Easily identified by its characteristic fluted, bamboo-like parallel ribs; abundant in Carboniferous coal-bearing strata across North America and Europe.

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