sedimentary

Weathered limestone fragment

Calcite-rich limestone, chiefly calcium carbonate (CaCO₃)

AI-generated identification · may be incorrect

Pale tan-gray, dull to slightly earthy luster, fine-grained and irregularly fractured; calcite hardness is Mohs 3, with weak cleavage and specific gravity about 2.7. The blurry image does not show crystals or fossils clearly.

Identified September 4, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when marine carbonate mud, shells, or chemical precipitates lithify; many limestones range from Paleozoic to Cenozoic in age. Weathering has rounded and stained this fragment.

Uses & applications

Used for aggregate, cement, lime, building stone, and landscaping; attractive fossiliferous or crystalline pieces may be collected, but this specimen appears low-value.

Geological facts

Limestone commonly reacts vigorously with dilute hydrochloric acid or household vinegar, producing bubbles from released carbon dioxide. It can recrystallize into marble during metamorphism.

Field identification & locations

Common worldwide, especially in former shallow marine basins; identify by pale color, relatively soft surface, and acid effervescence. Confirm with a scratch test and acid test on a fresh surface.