sedimentary
Limestone
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness of 3 on the Mohs scale, typically light gray, white, or tan in color, dull to earthy luster, fine-grained texture, and effervesces (fizzes) when exposed to hydrochloric acid.
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Physical properties
Hardness of 3 on the Mohs scale, typically light gray, white, or tan in color, dull to earthy luster, fine-grained texture, and effervesces (fizzes) when exposed to hydrochloric acid.
Formation & geological history
Formed by the accumulation of skeletal fragments from marine organisms such as coral, algal, and foraminifera, or through the chemical precipitation of calcium carbonate from water in marine or lacustrine environments.
Uses & applications
Extensively used in construction as building material, crushed stone for road bases, as a main ingredient in the manufacturing of cement, and in agriculture to neutralize acidic soils.
Geological facts
Limestone often contains well-preserved fossils of ancient sea life and makes up about 10% of the total volume of all sedimentary rocks on Earth. Famous structures like the Great Pyramids of Giza were built largely from limestone blocks.
Field identification & locations
Easily identified in the field by its light color, fine-grained appearance, and distinct fizzing reaction when tested with a weak acid like vinegar or hydrochloric acid. Found worldwide in regions with ancient shallow marine histories.
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