sedimentary

Crushed Limestone

Calcium Carbonate (CaCO3)

Hardness: 3 (Mohs scale); Color: Gray, off-white, buff; Luster: Dull to earthy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral; Specific gravity: 2.71

Hardness: 3 (Mohs scale)
Color: Gray, off-white, buff
Luster: Dull to earthy

Identified April 18, 2026More sedimentary →

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Physical properties

Hardness: 3 (Mohs scale); Color: Gray, off-white, buff; Luster: Dull to earthy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral; Specific gravity: 2.71

Formation & geological history

Formed through the accumulation of shell, coral, algal, and fecal debris in marine environments. It can also be formed by chemical precipitation from ocean or lake water. Geological ages vary, often dating to the Paleozoic or Mesozoic eras.

Uses & applications

Used extensively in construction for road base, railroad ballast, concrete aggregate, and as a soil conditioner in agriculture. It is also used in the manufacturing of cement and lime.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. It is the primary source of lime for cement, which is the world's most widely used building material.

Field identification & locations

Identify in the field by its characteristic gray color and its reaction (effervescence) when exposed to a drop of dilute hydrochloric acid. Commonly found in large quarry deposits globally.