sedimentary

Chalky limestone

Calcite-rich limestone; chiefly calcium carbonate (CaCO₃)

AI-generated identification · may be incorrect

Soft, pale cream to white, dull to earthy luster, massive/fine-grained texture; Mohs hardness about 3, commonly powders or scratches easily. Calcite may show rhombohedral cleavage and effervesces vigorously with dilute hydrochloric acid or vinegar, though the pictured surface appears weathered or coated.

Identified August 21, 2026More sedimentary →

Explore Chalky 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

Forms from accumulated marine shells, microscopic carbonate organisms, or lime mud, commonly during Phanerozoic marine sedimentation; exact age cannot be determined from the photograph.

Uses & applications

Used for cement, lime, soil treatment, aggregate, and building stone; attractive fossiliferous pieces are collected, but this specimen appears low-grade and unpolished.

Geological facts

The irregular raised patterns may be fossil fragments, bedding, or weathering rather than true crystals. Limestone can recrystallize into marble under heat and pressure.

Field identification & locations

Common worldwide in former shallow seas, including Europe, North America, North Africa, and Southeast Asia. Confirm with a fresh scratch and acid test; avoid acid if preservation or collecting value matters.