sedimentary
Fossiliferous Limestone
Biogenic Limestone (CaCO3 with fossil fragments)
AI-generated identification · may be incorrectHardness 3 on Mohs scale, earthy to dull luster, tan to light brown color with white fossilized bioclasts (such as crinoid stem segments and shell fragments), reacts readily with dilute hydrochloric acid.
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Physical properties
Hardness 3 on Mohs scale, earthy to dull luster, tan to light brown color with white fossilized bioclasts (such as crinoid stem segments and shell fragments), reacts readily with dilute hydrochloric acid.
Formation & geological history
Formed through the accumulation and compaction of organic debris, shell fragments, and skeletal remains of marine organisms in shallow, warm ocean environments over millions of years (commonly Paleozoic era).
Uses & applications
Used extensively in construction as dimension stone, gravel, and an ingredient in cement. Collected by fossil enthusiasts for educational and decorative purposes.
Geological facts
The circular white structure on the right is a fossilized crinoid columnal segment, often called 'St. Cuthbert's beads'. Crinoids are marine animals related to starfish and sea urchins.
Field identification & locations
Identified by its fine-grained matrix embedded with distinct calcified fossil fragments that bubble when tested with acid. Commonly found along ancient sea beds, riverbanks, and coastal beaches.
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