sedimentary
Calamites Fossil (Horsetail Stem)
Calamites (Genus), part of the class Equisetopsida
Hardness: 3-6 (variable based on matrix); Color: Grey, tan, or reddish-brown; Luster: Dull/Earthy; Structure: Characterized by vertical ribs and horizontal nodes or joints (segments) where leaves or branches once attached.
- Hardness
- 3-6 (variable based on matrix)
- Color
- Grey, tan, or reddish-brown
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3-6 (variable based on matrix); Color: Grey, tan, or reddish-brown; Luster: Dull/Earthy; Structure: Characterized by vertical ribs and horizontal nodes or joints (segments) where leaves or branches once attached.
Formation & geological history
Formed through the process of permineralization or cast-and-mold fossilization in coal-forming swamp environments during the Carboniferous period (approx. 360 to 300 million years ago).
Uses & applications
Primarily for scientific study, educational collections, and as a decorative geological specimen for collectors.
Geological facts
Calamites were tree-like plants that grew up to 30 meters (100 feet) tall. They are the ancient ancestors of the modern-day horsetail (Equisetum). Most fossilized specimens are actually the internal casts of the hollow stem.
Field identification & locations
Identify in the field by looking for distinct parallel ribbing and bamboo-like segments in sandstone, shale, or coal beds. They are commonly found in the Appalachian region of the USA, the UK, and Europe. Collectors should look for clear vertical lines and well-preserved 'nodes'.
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