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Coquina is a poorly cemented limestone that is composed of shells and remains of fossilized invertebrates like brachiopods, mollusks, and trilobites. It gets its name from the Spanish word for shellfish.

Coquina Polished
Coquina Classification
Common Name Coquina
Species Rock
Coquina Optical Properties
Dispersion Strength: None
Refractive Index 1.486-1.658
Birefringence 0.172
Pleochroism None
Coquina Characteristic Physical Properties
Hardness 1-2
Specific Gravity 1.100-2.240
Toughness Poor
Inclusions Shells and fossils
Luster Dull
Stability Good
Coquina Chemistry & Crystallography
Chemical Name calcium carbonate
Chemical Formula CaCO3

Coquina Colors

  • Brown Coquina Brown
  • Yellow Coquina Yellow
  • Gray Coquina Gray
  • White Coquina White

Countries of Origin



The Spanish started to use Coquina as a building material in Florida in 1598. In St. Augustine, the Castillo de San Marcos and the first lighthouse was constructed using Coquina. Because Coquina is so soft Cannonballs would embed into the walls of the fort instead of destroying them.


Soluble in hydrochloric acid.

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Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.