sedimentary

Polished fossiliferous limestone (likely fossil coral)

Fossiliferous limestone, chiefly calcite (CaCO₃), with fossil coral and shell fragments

AI-generated identification · may be incorrect

Polished, dark brown to gray stone with pale circular fossil cross-sections and a waxy-to-glassy surface. Calcite is Mohs 3, trigonal; limestone hardness varies, and dilute acid typically fizzes on exposed calcite.

Identified October 7, 2026More sedimentary →

Explore Polished fossiliferous limestone (likely fossil coral) 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

Marine carbonate sediment accumulated on an ancient seafloor, then lithified and fossilized; age cannot be determined from the image alone. The visible patterns are consistent with preserved coral or other marine fossils.

Uses & applications

Used as a polished decorative specimen, paperweight, or ornamental stone; fossiliferous limestone is also used as building stone and aggregate.

Geological facts

Polishing highlights fossil structures that may be difficult to see on a weathered surface.

Field identification & locations

Look for repeated fossil-like rings or chambers embedded in a continuous carbonate matrix; common sources include sedimentary basins and former reef deposits worldwide. A simple acid test on an inconspicuous spot can help confirm calcite.