sedimentary
Limestone (or Chalk / Calcite fragment)
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectMohs hardness of 3; white to light gray with an earthy, dull luster and fine-grained to microcrystalline texture.
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Physical properties
Mohs hardness of 3; white to light gray with an earthy, dull luster and fine-grained to microcrystalline texture.
Formation & geological history
Formed through the accumulation and compaction of microscopic marine organism shells and biochemical calcium carbonate precipitates.
Uses & applications
Widely used as crushed stone for construction aggregate, lime production, cement manufacturing, and soil conditioning.
Geological facts
Limestone readily dissolves in mild acidic rainwater, leading to the formation of extensive karst landscapes and deep cave systems worldwide.
Field identification & locations
Identifiable in the field by its softness (easily scratched by a copper penny or steel nail) and vigorous effervescence in dilute hydrochloric acid.
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