Rock Identifier
Limestone Pebble (Calcium Carbonate (CaCO3)) — sedimentary
sedimentary

Limestone Pebble

Calcium Carbonate (CaCO3)

Mohs hardness of 3, light gray to white color, dull to earthy luster, fine-grained microcrystalline structure, poor cleavage, specific gravity around 2.7.

Identified More sedimentary
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Physical properties

Mohs hardness of 3, light gray to white color, dull to earthy luster, fine-grained microcrystalline structure, poor cleavage, specific gravity around 2.7.

Formation & geological history

Formed from the accumulation of skeletal fragments of marine organisms and shell debris in shallow marine environments, typically over millions of years, then subsequently weathered and water-worn into a smooth pebble.

Uses & applications

Used in construction, aggregate for concrete, road base, and agricultural lime.

Geological facts

Limestone often weathers to form distinctive karst topography featuring caves and sinkholes due to its solubility in slightly acidic water.

Field identification & locations

Commonly found in stream beds and beaches near sedimentary rock formations; easily identified by its characteristic reaction (effervescence) when exposed to weak acid like vinegar.