sedimentary

Fossiliferous limestone, possibly a shell or bone fragment

Calcitic limestone; predominantly calcium carbonate (CaCO₃), likely calcite

AI-generated identification · may be incorrect

Gray-beige, fine-grained, dull to slightly earthy luster, with a prominent raised seam or internal structure and pale mineral veins. Calcite has Mohs hardness 3, rhombohedral cleavage, and specific gravity about 2.7; it should fizz with dilute hydrochloric acid.

Identified September 21, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from accumulated marine carbonate mud or biological material, later lithified and fractured; the apparent seam may represent fossil structure, bedding, or a calcite-filled crack. Such limestones commonly range from Paleozoic to Cenozoic in age, but the specimen’s age cannot be determined from the image.

Uses & applications

Used for aggregate, cement, lime, building stone, and occasionally decorative specimens; fossil-bearing pieces are collected for educational and display value.

Geological facts

The angular fragment shows no obvious crystalline texture, making a limestone or fossil fragment more likely than a crystalline igneous rock. A vinegar test may produce weak bubbling, while hydrochloric acid gives a stronger reaction.

Field identification & locations

Common in former shallow-marine environments worldwide, especially Europe, North America, and the Middle East. Examine broken surfaces for shell chambers, bone pores, or sedimentary layering; avoid acid testing on valuable specimens.