sedimentary
Limestone (River Pebble)
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness 3 on Mohs scale, grayish-white to tan color, dull to earthy luster, microcrystalline, reacts strongly with dilute hydrochloric acid.
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Physical properties
Hardness 3 on Mohs scale, grayish-white to tan color, dull to earthy luster, microcrystalline, reacts strongly with dilute hydrochloric acid.
Formation & geological history
Formed in shallow marine environments from the accumulation of organic debris, shell fragments, and calcium carbonate precipitation. Later weathered and rounded by river action.
Uses & applications
Used in construction as aggregate, in lime manufacturing, soil neutralization, and as common decorative garden stones.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks. It is the primary component of karst landscapes which form caves and sinkholes.
Field identification & locations
Easily identified in the field by its softness relative to quartz and its effervescence when exposed to acid. Commonly found in stream beds, river banks, and exposed sedimentary rock formations worldwide.
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