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Coquina identification and geology

Coquina rock reference specimen

Poorly cemented sedimentary rock composed almost entirely of shell fragments and other bioclasts. Texture: Bioclastic. Rock type: Sedimentary Biochemical. Grain size: Coarse shell fragments. Minerals present: Calcite from shells, Aragonite. Formation: Forms from accumulation and loose cementation of shells in high-energy nearshore environments. Common geological settings: Florida USA , Brazil, North Africa; found in coastal and nearshore environments. Common look-alikes and related entries: Limestone, Fossiliferous Limestone, Chalk.

Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

Editorial owner
GeoMiner
Last updated
2026-03-30T14:38:28.134883+00:00
Review status
Published; not independently peer-reviewed
  • Rocks — U.S. National Park Service. Authoritative overview of rock groups, the rock cycle, and geologic processes.
  • Can you identify my rock or mineral? — U.S. Geological Survey. Identification limitations and routes to in-person professional verification.

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Common questions

What is Coquina?
Poorly cemented sedimentary rock composed almost entirely of shell fragments and other bioclasts.
How can you identify Coquina?
Compare several properties rather than relying on colour alone. This entry records rock type: Sedimentary Biochemical; texture: Bioclastic; grain size: Coarse shell fragments; common minerals: Calcite from shells, Aragonite. Confirm an important identification with additional field tests or qualified laboratory work.
How does Coquina form?
Forms from accumulation and loose cementation of shells in high-energy nearshore environments.
Where is Coquina commonly found?
Florida USA , Brazil, North Africa; found in coastal and nearshore environments.
What is Coquina commonly confused with?
Coquina may be confused with Limestone, Fossiliferous Limestone, Chalk. Compare multiple diagnostic properties because colour and surface appearance can overlap.

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