sedimentary
Coquina
Bioclastic Sedimentary Rock
AI-generated identification · may be incorrectHardness varies from 3 to 4 on the Mohs scale depending on cementation, white to yellowish-tan color, dull luster, composed of poorly cemented shell fragments, no specific crystal structure.
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Physical properties
Hardness varies from 3 to 4 on the Mohs scale depending on cementation, white to yellowish-tan color, dull luster, composed of poorly cemented shell fragments, no specific crystal structure.
Formation & geological history
Formed in high-energy marine environments where waves accumulate and cement calcium carbonate shell fragments together. Geologically young to ancient formations.
Uses & applications
Used locally as a building stone, in road construction, and historically for coastal fortifications like Castillo de San Marcos.
Geological facts
Coquina means shellfish or cockle shell in Spanish. It is a unique rock type because it consists almost entirely of visible fossilized shells.
Field identification & locations
Easily identified by its distinct chalky, porous appearance packed with visible marine shells. Found in coastal regions, notably Florida and North Carolina.
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