sedimentary
Chalk
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness: 2-3 (Mohs scale), Color: White to grey, Luster: Dull/Earthy, Structure: Microcrystalline/Amorphous, Density: 2.2-2.3 g/cm3
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Physical properties
Hardness: 2-3 (Mohs scale), Color: White to grey, Luster: Dull/Earthy, Structure: Microcrystalline/Amorphous, Density: 2.2-2.3 g/cm3
Formation & geological history
Formed in deep marine environments from the accumulation of microscopic skeletal remains (coccospheres) of marine algae during the Cretaceous period.
Uses & applications
Used in agriculture for soil treatment, production of lime, construction material as Portland cement, and traditionally as a drawing instrument.
Geological facts
The word 'Cretaceous' comes from the Latin word 'creta' meaning chalk, reflecting the vast deposits formed during that era. The White Cliffs of Dover are the most famous example.
Field identification & locations
Identify by its soft texture, ability to leave a white streak on dark surfaces, and violent effervescence when exposed to dilute hydrochloric acid. Commonly found in coastal chalk landscapes.
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