sedimentary

Limestone (Weathered)

Calcium Carbonate (CaCO3)

Hardness: 3 on the Mohs scale. Color: Grayish-brown, weathered gray. Luster: Dull or earthy. Crystal structure: Microcrystalline or cryptocrystalline calcite. Cleavage: Perfect rhombohedral cleavage in pure crystals, but often absent or obscured in dense varieties. Specific gravity: 2.7 to 2.9.

Hardness: 3 on the Mohs scale
Color: Grayish-brown, weathered gray
Luster: Dull or earthy

Identified August 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation and compaction of organic remains such as shells, coral, and algal debris, or through the chemical precipitation of calcium carbonate from marine water over millions of years. This particular specimen shows extensive dissolution features (karst weathering/solution pits).

Uses & applications

Used widely in construction (aggregate, cement, building stone), agriculture (soil conditioning), and industrial chemical processes.

Geological facts

Limestone landscapes often feature caves, sinkholes, and underground drainage systems due to the high solubility of calcium carbonate in slightly acidic groundwater.

Field identification & locations

Easily identifiable in the field by its characteristic reaction to dilute hydrochloric acid (it effervesces or fizzes) and its lower hardness, allowing it to be scratched easily with a knife.

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