sedimentary

Polished fossiliferous limestone

Bioclastic limestone, commonly crinoidal limestone (calcite, CaCO₃)

AI-generated identification · may be incorrect

Typically Mohs hardness 3, with a dull to waxy polish, cream-gold to brown color, and visible fossil fragments or stem segments in a calcite matrix. It is generally massive, lacks cleavage as a rock, and effervesces strongly with dilute hydrochloric acid.

Identified August 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when marine skeletal debris—often crinoids, shell fragments, or bryozoans—accumulates, is compacted, and cemented in shallow seas. Such fossiliferous limestones range from Paleozoic to younger ages; the specimen appears cut and polished.

Uses & applications

Used as decorative stone, cabochons, bookends, and educational or fossil-collecting specimens; limestone is also widely used for cement, aggregate, and building stone.

Geological facts

The elongated pale pieces may be crinoid columnals, commonly called “海 lilies,” though exact fossil identification requires magnification. Calcite fossils can recrystallize during burial while retaining their outlines.

Field identification & locations

Look for repeated fossil shapes, a soft scratch response to steel, and acid fizz; avoid vinegar if preserving the polish. Common sources include Paleozoic marine limestone regions in North America and Europe.