sedimentary

Polished fossiliferous limestone (likely crinoidal or coral limestone)

Bioclastic carbonate rock, chiefly calcite (CaCO₃)

AI-generated identification · may be incorrect

Brown, rounded and polished, with lighter fossil-like circular/irregular inclusions and dull to slightly waxy luster. Calcite has Mohs hardness 3, rhombohedral cleavage, and specific gravity about 2.7; it effervesces strongly with dilute hydrochloric acid.

Identified September 4, 2026More sedimentary →

Explore Polished fossiliferous limestone (likely crinoidal or coral limestone) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed from accumulated marine skeletal debris that lithified into limestone, commonly during Paleozoic–Mesozoic marine deposition; its exact age cannot be determined from the photograph. The rounded shape and surface sheen indicate later tumbling or polishing.

Uses & applications

Used as a decorative polished specimen, paperweight, or cabochon material; limestone is also important for cement, aggregate, lime, and building stone. Fossil-rich pieces have modest collector interest.

Geological facts

The pale markings may represent crinoid columnals, shell fragments, or corals, but photography alone cannot confirm the fossil type. Brown coloration commonly results from iron oxides or organic matter.

Field identification & locations

Look for visible fossil structures, a relatively soft surface, and acid reaction; a steel knife may scratch it. Common sources include marine limestone regions worldwide, including Europe, North America, and Asia.