sedimentary
Fossilized Brain Coral
Diploria labyrinthiformis (Fossilized)
Hardness: 3-4 (Mohs scale); Color: White, cream, or light tan; Luster: Dull to earthy; Structure: Sinuous, maze-like ridges (meandering septa); Cleavage: None; Composition: Calcium carbonate (Calcite/Aragonite) or Silica if silicified.
- Hardness
- 3-4 (Mohs scale)
- Color
- White, cream, or light tan
- Luster
- Dull to earthy
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Physical properties
Hardness: 3-4 (Mohs scale); Color: White, cream, or light tan; Luster: Dull to earthy; Structure: Sinuous, maze-like ridges (meandering septa); Cleavage: None; Composition: Calcium carbonate (Calcite/Aragonite) or Silica if silicified.
Formation & geological history
Formed through the fossilization of stony coral colonies. The original organic structure is replaced by minerals over thousands to millions of years in shallow marine environments. Often found in limestone deposits from the Pleistocene or Holocene.
Uses & applications
Collecting, decorative home accents, aquarium decor, and educational geological specimens.
Geological facts
The name 'Brain Coral' comes from the labyrinthine appearance which resembles the folds of a human brain. Individual polyps live in the grooves and build the calcium carbonate skeleton.
Field identification & locations
Identified by the distinct wandering grooves and ridges. Commonly found on beaches near coral reefs or in inland sedimentary rock formations that were once underwater. Collectors look for well-defined patterns and lack of erosion.
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