sedimentary

Vesicular limestone or calcareous tufa

Calcite-rich carbonate rock; predominantly CaCO₃, commonly aragonite/calcite

AI-generated identification · may be incorrect

Hardness about 3 Mohs; cream to tan, earthy/dull luster, highly porous and irregularly cavity-filled. It reacts vigorously with dilute hydrochloric acid or vinegar, unlike most silicate rocks.

Identified September 9, 2026More sedimentary →

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Physical properties

Hardness about 3 Mohs; cream to tan, earthy/dull luster, highly porous and irregularly cavity-filled. It reacts vigorously with dilute hydrochloric acid or vinegar, unlike most silicate rocks.

Formation & geological history

Likely formed by precipitation of carbonate from groundwater or spring water around voids, organisms, or plant material; commonly Quaternary to recent, though similar porous limestones can be older.

Uses & applications

Used locally as lightweight decorative stone, landscaping material, and occasionally building stone; specimens have modest collecting value.

Geological facts

The cavities may be molds of dissolved shells, plant matter, or gas spaces, and brown areas may represent iron-oxide staining or incorporated sediment.

Field identification & locations

Identify it by its very low density, abundant cavities, chalky carbonate texture, and acid effervescence; common in limestone terrains, caves, springs, and arid calcareous deposits.