fossil

Tumbled fossiliferous limestone

Bioclastic limestone, primarily calcite (CaCO₃)

AI-generated identification · may be incorrect

Brown, cream, and gray polished surface with abundant small fossil or pore-like structures; vitreous to dull luster. Calcite hardness is Mohs 3, with irregular fracture and weak-to-no cleavage in the tumbled form; reacts vigorously with dilute hydrochloric acid.

Identified September 2, 2026More fossil →

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Physical properties

Formation & geological history

Formed from compacted and cemented marine shell, coral, or skeletal debris, commonly during the Paleozoic–Cenozoic eras; later weathering and tumbling rounded the specimen.

Uses & applications

Used as a decorative stone, educational specimen, and lapidary material; limestone is widely used for cement, aggregate, and building stone. This small polished piece has modest collector value.

Geological facts

The visible cavities may represent dissolved fossil fragments, shell pores, or vugs rather than crystals. A streak or powder that fizzes with acid strongly supports calcite-rich limestone.

Field identification & locations

Common in former shallow-marine sedimentary basins worldwide, including the Great Lakes region, Europe, and the Caribbean. Inspect cavities for recognizable shells or coral and avoid confusing it with porous slag or concrete.