sedimentary
Chalk
Calcareous sedimentary rock (CaCO3)
AI-generated identification · may be incorrectHardness of 1 on the Mohs scale, white or greyish color, earthy luster, soft and fine-grained texture.
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Physical properties
Hardness of 1 on the Mohs scale, white or greyish color, earthy luster, soft and fine-grained texture.
Formation & geological history
Formed by the accumulation of microscopic calcareous shells of marine microorganisms like coccolithophores over millions of years.
Uses & applications
Used in agriculture for soil conditioning, manufacturing of lime, traditional blackboard chalk, and in various construction materials.
Geological facts
Chalk deposits formed extensively during the Cretaceous period, which derives its name from the Latin word for chalk, creta.
Field identification & locations
Easily identified by its soft, powdery texture and effervescence when exposed to dilute hydrochloric acid. Found worldwide in marine sedimentary basins.
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