sedimentary

Limestone (Weathered Pebble)

Calcium Carbonate (CaCO3) / Limestone

AI-generated identification · may be incorrect

Hardness: 3 on Mohs scale; Color: Medium to dark gray with white highlights; Luster: Dull to earthy; Texture: Fine-grained, weathered surface with small pits and solution cavities; Specific Gravity: 2.5–2.7

Hardness: 3 on Mohs scale
Color: Medium to dark gray with white highlights
Luster: Dull to earthy

Identified July 24, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and compaction of organic debris like coral, shells, and micro-fossils or by chemical precipitation of calcium carbonate in shallow marine environments over millions of years. This pebble has undergone subsequent water and atmospheric erosion.

Uses & applications

Limestone is widely used in construction as crushed stone, in cement production, soil stabilization, and as raw material for chemical manufacturing. Smooth beach/river pebbles are often used for decorative landscaping.

Geological facts

Limestone dissolves slowly in weakly acidic rainwater, which creates the characteristic pitted surface (karst features) visible on this weathered pebble. It is one of the most common sedimentary rocks on Earth.

Field identification & locations

Identified by its gray dull tone, fine grain, pitted weathered exterior, and reaction (effervescence) when exposed to cold dilute hydrochloric acid or household vinegar. Commonly found along riverbeds, lakeshores, and marine beaches.