sedimentary

Crinoid and Coral Fossils in Limestone

Fossiliferous Limestone with Rugosa (order) and Crinoidea (class)

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs); Color: Grey, tan, or charcoal; Luster: Dull/Earthy; Structure: Visible honeycomb-like coral patterns and disc-like crinoid stem fragments embedded in a fine-grained matrix.

Hardness: 3-4 (Mohs)
Color: Grey, tan, or charcoal
Luster: Dull/Earthy

Identified May 4, 2026More sedimentary →

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Physical properties

Hardness: 3-4 (Mohs); Color: Grey, tan, or charcoal; Luster: Dull/Earthy; Structure: Visible honeycomb-like coral patterns and disc-like crinoid stem fragments embedded in a fine-grained matrix.

Formation & geological history

Formed in shallow, warm marine environments where biological debris accumulated and was buried and lithified over millions of years, typically during the Paleozoic Era (485-252 million years ago).

Uses & applications

Primarily used for geological study, education, fossil collecting, and occasionally as decorative stone or garden ornaments.

Geological facts

This specimen contains 'honeycomb' patterns likely from colonial rugose or tabulate corals and segmented sections representing crinoids, often called 'sea lilies' which are animals related to starfish.

Field identification & locations

Identify by looking for repeating geometric patterns (pentagons/hexagons) and circular stem cross-sections. Commonly found in riverbeds or outcrops in areas with Paleozoic bedrock.