sedimentary
Fossiliferous Limestone with Rugose Coral
Lithostrotionella (Limestone Matrix - CaCO3)
Hardness 3-4 (Mohs), Gray to tan color, Earthy to dull luster, Fine-grained texture with circular fossil inclusions, Reacts with HCl acid.
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Physical properties
Hardness 3-4 (Mohs), Gray to tan color, Earthy to dull luster, Fine-grained texture with circular fossil inclusions, Reacts with HCl acid.
Formation & geological history
Formed in warm, shallow marine environments during the Paleozoic era (approx. 300-350 million years ago) through the accumulation of calcium carbonate and coral skeletons.
Uses & applications
Used primarily in aggregate, cement production, architectural stone, and as educational fossil specimens for collectors.
Geological facts
The circular pits in this specimen are cross-sections of rugose corals, also known as horn corals, which were major reef builders before the Permian mass extinction.
Field identification & locations
Identify by looking for circular or star-shaped organic patterns embedded in a soft, light-colored matrix. Commonly found in road cuts and riverbeds of the American Midwest and UK.
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