sedimentary

Weathered limestone or calcareous fossil fragment

Calcite-rich carbonate rock (CaCO₃), possibly fossiliferous limestone

AI-generated identification · may be incorrect

Likely calcite-dominant, off-white to tan with brown weathering and a dull earthy luster; hardness about 3 Mohs, generally massive with no obvious cleavage visible. The irregular porous form may reflect a worn fossil or carbonate fragment.

Identified August 11, 2026More sedimentary →

Explore Weathered limestone or calcareous fossil fragment 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 shells, skeletal debris, or carbonate mud that lithified into limestone, commonly during the Paleozoic–Cenozoic eras; surface weathering and abrasion produced its rounded shape.

Uses & applications

Used as aggregate, building stone, cement and lime feedstock; this small specimen has mainly educational or decorative value rather than jewelry use.

Geological facts

Calcite effervesces visibly in dilute hydrochloric acid or strong vinegar, unlike most silicate rocks. Brown patches may be iron-oxide staining or preserved organic material.

Field identification & locations

Common in marine sedimentary terrains worldwide, especially around limestone coastlines and karst regions. Identify it by its light color, softness, lack of glassy luster, and acid reaction; a fossil texture would support the identification.