fossil

Fossiliferous Limestone (Crinoid stem fragments)

Bioclast-bearing Carbonate Rock (Caco3)

Hardness: 3-4 (Mohs scale); Color: Dark grey to charcoal matrix with light grey circular inclusions; Luster: Dull/Earthy; Structure: Fine-grained matrix with fossiliferous clasts; Cleavage: None (concretionary/irregular fracture)

Hardness: 3-4 (Mohs scale)
Luster: Dull/Earthy

Identified July 4, 2026More fossil →

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Physical properties

Formation & geological history

Formed in shallow marine environments during the Paleozoic era (approx. 300-450 million years ago) through the accumulation of skeletal remains and calcium carbonate mud

Uses & applications

Used as building stone, in the production of cement and lime, and as ornamental specimens for geological study

Geological facts

The circular patterns are cross-sections of crinoid stems, also known as 'sea lilies,' which are echinoderms related to starfish and sea urchins. They were extremely abundant in ancient seas.

Field identification & locations

Look for small 'cheerio' or circular ring shapes in dark, fine-grained rock. Often found in areas with exposed Devonian or Carboniferous strata. It will react and fizz if a drop of weak acid is applied.

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