sedimentary

Limestone Gravel

Calcium Carbonate (CaCO3)

Porous texture, off-white to light gray color, dull luster, Mohs hardness of 3, reacts with dilute acid, contains calcite or aragonite minerals.

Identified June 1, 2026More sedimentary →

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Physical properties

Porous texture, off-white to light gray color, dull luster, Mohs hardness of 3, reacts with dilute acid, contains calcite or aragonite minerals.

Formation & geological history

Formed primarily from the accumulation of skeletal fragments of marine organisms like coral or foraminifera in shallow marine environments over millions of years.

Uses & applications

Commonly used as construction aggregate, road base, landscaping gravel, and for soil pH adjustment in agriculture.

Geological facts

Limestone makes up about 10 percent of the total volume of all sedimentary rocks globally. It is the primary material used for making Portland cement.

Field identification & locations

Identified in the field by its light color and characteristic fizzing reaction (effervescence) when exposed to a drop of white vinegar or hydrochloric acid. Found in quarries worldwide.