sedimentary
Coquina (Hag Stone variant)
Biocalcarenite (Coquina)
Hardness: 2-3 (Mohs scale); Color: Tan, cream, off-white; Luster: Dull to earthy; Composition: Skeletal fragments of mollusks and invertebrates; Structure: Porous, clastic texture with natural perforations.
- Hardness
- 2-3 (Mohs scale)
- Color
- Tan, cream, off-white
- Luster
- Dull to earthy
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Physical properties
Hardness: 2-3 (Mohs scale); Color: Tan, cream, off-white; Luster: Dull to earthy; Composition: Skeletal fragments of mollusks and invertebrates; Structure: Porous, clastic texture with natural perforations.
Formation & geological history
Formed in high-energy marine environments where shell fragments accumulate and are cemented together by calcium carbonate. This specific specimen has undergone mechanical erosion (wave action) to create natural holes.
Uses & applications
Used in landscaping, historical road construction (Florida/coastal regions), and as cultural amulets or 'fairy stones' in folklore.
Geological facts
Rocks with natural holes, like this one, are often called 'Hag Stones' in folklore and were historically believed to ward off evil or provide protection to sailors.
Field identification & locations
Look for rounded, weathered edges and natural circular perforations called 'vugs'. Found commonly along shorelines with high shell concentration or ancient seafloors.
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