sedimentary

Porous limestone

Calcite-rich limestone (predominantly CaCO₃)

AI-generated identification · may be incorrect

Pale cream to tan, rough and highly porous, with a dull earthy luster; likely Mohs hardness 3, though the specimen’s texture makes testing uncertain. Limestone is chiefly calcite and may contain shell fragments or other minerals; crystal structure is trigonal.

Identified October 15, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms through accumulation and lithification of carbonate mud, shells, or chemical precipitates, commonly in marine settings. Its age cannot be determined from the image.

Uses & applications

Limestone is widely used for cement and lime production, aggregate, building stone, and agricultural soil treatment; this rough piece appears to be a common hand specimen.

Geological facts

Calcite-rich limestone reacts with dilute acid, often fizzing; porosity can result from fossils, dissolution, or weathering.

Field identification & locations

The light color and porous, carbonate-like texture suggest limestone, but visual identification is not conclusive; an acid reaction or examination for fossils can help. Limestone occurs worldwide, especially in former marine basins.