sedimentary

Fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃), with fossil shell or coral fragments

AI-generated identification · may be incorrect

Typically cream, gray, and brown with visible elongated shell/coral structures; dull to weakly crystalline, Mohs hardness about 3, good cleavage in calcite, and specific gravity around 2.7. It effervesces strongly with dilute hydrochloric acid or vinegar, though weathered surfaces may react weakly.

Identified September 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms from accumulation, burial, compaction, and cementation of marine skeletal debris in shallow seas; age cannot be determined from the image and may range from Paleozoic to Cenozoic. Later recrystallization can produce the pale translucent calcite bands.

Uses & applications

Used as dimension stone, aggregate, cement and lime feedstock; attractive polished pieces are sold as decorative stone or fossil specimens. Jewelry use is limited because calcite is soft and easily scratched.

Geological facts

The elongated white forms may be fossil shells, bryozoans, crinoid fragments, or altered coral, but exact identification requires close examination. Field identification relies on fossils, granular texture, and acid reaction.

Field identification & locations

Common in marine sedimentary basins worldwide, including Europe, North America, North Africa, and Southeast Asia; avoid confusing it with marble, which has a more uniformly crystalline texture. Estimated value: $5–$30 for a common hand specimen, or $30–$150 if fossils are exceptionally preserved and attractive.