sedimentary

Porous limestone pebble

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

AI-generated identification · may be incorrect

Pale gray to cream, dull and rough, with irregular cavities and a rounded shape. Calcite has Mohs hardness 3 and trigonal crystal structure; limestone commonly reacts with dilute acid, but no test is shown.

Identified October 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed from accumulated carbonate sediment or shell material, later compacted and cemented; the pebble’s age and source cannot be determined from appearance alone.

Uses & applications

Ordinary limestone is used for cement, lime, aggregate, and building stone; this small porous pebble has little practical or jewelry use.

Geological facts

The holes may reflect dissolved fossil or shell material, or weathering; no definite fossil structures are visible.

Field identification & locations

A carbonate-rich appearance and possible fizz with dilute acid help identify limestone; look for it in sedimentary terrains, stream beds, and coastal deposits. The image alone cannot establish the specimen’s exact rock type.