sedimentary

Limestone Pebble

Limestone (Calcium Carbonate, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs scale), Color: light gray to tan, Luster: dull to earthy, Texture: fine-grained (micritic), Specific Gravity: 2.3-2.7

Identified July 14, 2026More sedimentary →

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Physical properties

Hardness: 3-4 (Mohs scale), Color: light gray to tan, Luster: dull to earthy, Texture: fine-grained (micritic), Specific Gravity: 2.3-2.7

Formation & geological history

Formed by the accumulation of shells, coral, algal, and fecal debris in clear, warm, shallow marine waters. This specific specimen appears water-worn, likely from a river or beach environment.

Uses & applications

Limestone is extensively used as a building material, aggregate for concrete, and in the production of cement and lime. Small pebbles are often used for landscaping or as aquarium decor.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. It is soluble in weak acids, which is why it often contains caves and karst topography.

Field identification & locations

Identify in the field by its softness (can be scratched by a steel nail) and its effervescence (bubbling) when exposed to a drop of weak acid such as vinegar. Common in ancient seabed regions.