sedimentary

Limestone

Calcium Carbonate (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3 (Mohs scale), Color: tan-grey to buff, Luster: dull/earthy, Crystal structure: Trigonal (microcrystalline), Cleavage: None visible in hand specimen

Identified July 6, 2026More sedimentary →

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Physical properties

Hardness: 3 (Mohs scale), Color: tan-grey to buff, Luster: dull/earthy, Crystal structure: Trigonal (microcrystalline), Cleavage: None visible in hand specimen

Formation & geological history

Formed from the accumulation of shell, coral, algal, and fecal debris in marine environments. Often dates back hundreds of millions of years in Paleozoic or Mesozoic seabed deposits.

Uses & applications

Used primarily in building materials, cement production, agriculture to neutralize soil acidity, and as a crushed aggregate for road construction.

Geological facts

Limestone is the primary rock type found in karst landscapes, which feature caves and sinkholes due to the rock\'s solubility in slightly acidic rainwater.

Field identification & locations

Can be identified in the field by its tendency to fizz when a small amount of dilute acid (like vinegar) is applied. Often contains visible tiny marine fossils or impressions.