sedimentary
Chalk
Sedimentary Rock (Calcium Carbonate, CaCO3)
AI-generated identification · may be incorrectHardness of 1 on the Mohs scale, white or light gray color, earthy luster, microcrystalline structure, specific gravity around 1.9 to 2.5.
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Physical properties
Hardness of 1 on the Mohs scale, white or light gray color, earthy luster, microcrystalline structure, specific gravity around 1.9 to 2.5.
Formation & geological history
Formed from the accumulation of microscopic calcareous shells of marine organisms like coccolithophores during the Cretaceous period.
Uses & applications
Used in agriculture for soil pH adjustment, manufacturing lime, cement, and traditionally for blackboard chalk.
Geological facts
Chalk deposits form the famous White Cliffs of Dover in England and accumulated over millions of years.
Field identification & locations
Easily identified by its soft, powdery texture and vigorous fizzing reaction when exposed to dilute hydrochloric acid.
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