sedimentary

Limestone Pebble

Sedimentary Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: Gray with white calcite veining; Luster: Dull to earthy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture).

Hardness: 3 on Mohs scale
Color: Gray with white calcite veining
Luster: Dull to earthy

Identified June 25, 2026More sedimentary →

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Physical properties

Hardness: 3 on Mohs scale; Color: Gray with white calcite veining; Luster: Dull to earthy; Structure: Microcrystalline; Cleavage: None (conchoidal fracture).

Formation & geological history

Formed by the accumulation of shell, coral, algal, and fecal debris in clear, warm, shallow marine waters. This specific pebble has been water-worn and smoothed by river or beach erosion.

Uses & applications

Used primarily in the production of cement, as a soil conditioner in agriculture, and as crushed stone for road bases. Polished pebbles are used in landscaping and home decor.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. It is the primary source material for the formation of spectacular karst landscapes and caves.

Field identification & locations

Identified by its gray color, white veins, and Reactivity to dilute hydrochloric acid (it will fizz). Commonly found in riverbeds, beaches, and ancient seabed outcrops.