sedimentary

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous

AI-generated identification · may be incorrect

Pale tan-gray, dull to slightly sugary luster, fine to medium crystalline texture, irregular fractures and weathered cavities; calcite hardness is about Mohs 3, and it should fizz with dilute hydrochloric acid or strong vinegar. The rounded shape suggests natural abrasion or tumbling.

Identified August 8, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from compacted and cemented carbonate mud, shells, or other marine sediments, commonly during Paleozoic–Cenozoic marine deposition; the exact age cannot be determined from the photograph.

Uses & applications

Used widely as aggregate, cement and lime feedstock, building stone, and soil-neutralizing material; attractive pieces may be kept as display specimens, though this example appears common and unpolished.

Geological facts

Limestone is particularly vulnerable to dissolution by weak acids, producing caves, karst landscapes, and sinkholes. Surface pits may reflect dissolved fossil fragments or weathered carbonate grains.

Field identification & locations

Common worldwide, especially in former shallow-marine regions. Identify it by its light color, relatively soft surface, carbonate fizz, and lack of obvious glassy quartz; a hardness test and acid test would distinguish it from quartzite or sandstone.