sedimentary

Weathered limestone fragment, possibly fossiliferous

Calcite-rich limestone (CaCO₃); exact identification is uncertain from one image

AI-generated identification · may be incorrect

Tan to gray, porous and strongly weathered, with dull to earthy luster and no obvious crystals. Calcite hardness is Mohs 3, typically with irregular fracture; it should effervesce vigorously with dilute hydrochloric acid or vinegar if sufficiently fresh.

Identified August 19, 2026More sedimentary →

Explore Weathered limestone fragment, possibly fossiliferous 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 carbonate mud, shells, or skeletal debris that lithify into limestone, commonly in shallow marine environments. The cavity and irregular texture may represent dissolved fossil material or weathering; age cannot be determined visually.

Uses & applications

Used as aggregate, cement and lime feedstock, building stone, and soil conditioner. This small weathered piece has little commercial or jewelry value.

Geological facts

Limestone is dominated by calcite and may preserve abundant fossils. Surface alteration can make it resemble weathered bone, concrete, or porous volcanic rock.

Field identification & locations

Common worldwide, especially in former seabeds and karst regions. Look for acid reaction, soft scratching by a steel nail, and possible shell or fossil patterns; a close-up of fresh surfaces would improve identification.