sedimentary

Limestone (Riprap)

Calcium Carbonate (CaCO3)

Hardness: 3-4 (Mohs scale); Color: light grey to buff; Luster: dull to earthy; Structure: non-clastic, fine-grained; often contains fossil fragments.

Hardness: 3-4 (Mohs scale)
Color: light grey to buff
Luster: dull to earthy

Identified July 4, 2026More sedimentary →

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Physical properties

Hardness: 3-4 (Mohs scale); Color: light grey to buff; Luster: dull to earthy; Structure: non-clastic, fine-grained; often contains fossil fragments.

Formation & geological history

Formed by the accumulation of shell, coral, algal, and fecal debris in warm, shallow marine waters. These specific boulders are likely sourced from a limestone quarry to be used as shoreline armor.

Uses & applications

Used primarily for coastal protection (riprap), erosion control, construction aggregate, and in the production of cement and lime.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. It is essential for human life as it is the primary source of lime used in agriculture and steel production.

Field identification & locations

Identify by its grey color, presence of marine fossils, and its reaction (effervescence) when touched with dilute hydrochloric acid. Commonly found in coastal engineering projects.