sedimentary
Chalk
Sedimentary rock composed of calcite (CaCO3)
AI-generated identification · may be incorrectMohs hardness of 1 to 2, white or light gray color, earthy luster, and microcrystalline structure.
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Physical properties
Mohs hardness of 1 to 2, white or light gray color, earthy luster, and microcrystalline structure.
Formation & geological history
Formed from the accumulation of microscopic marine plankton skeletal remains over millions of years during the Cretaceous period.
Uses & applications
Used in agriculture for soil neutralization, manufacturing of lime and cement, and traditionally for writing surfaces.
Geological facts
Chalk deposits form iconic white cliffs, such as those found along the coast of Dover in southern England.
Field identification & locations
Easily identified by its soft, powdery texture and strong fizzing reaction when exposed to dilute hydrochloric acid.
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