Coquina

Rock

By Tim Matthews, JD, FGA, GG, DGA,
CEO and President of JTV (retired)
Published: June 2014
Modified: October 2021
Coquina Polished Coquina Rough

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.

General Information

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

Coquina Colors

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

Countries of Origin

Unknown; India

History

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 were constructed using coquina. Because coquina is so soft, cannonballs would embed into the walls of the fort instead of destroying them.

Care

Soluble in hydrochloric acid.