fossil
Fossilized Coral (Petrified Coral)
Lithostrotionella (example genus) / Scleractinia
Hardness: 6.5-7 Mohs; Color: White, cream, tan; Luster: Waxy to dull; Crystal structure: Hexagonal/Trigonal silica replacement; Specific Gravity: 2.6-2.7
- Hardness
- 6
- Color
- White, cream, tan
- Luster
- Waxy to dull
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Physical properties
Hardness: 6.5-7 Mohs; Color: White, cream, tan; Luster: Waxy to dull; Crystal structure: Hexagonal/Trigonal silica replacement; Specific Gravity: 2.6-2.7
Formation & geological history
Formed when ancient coral reefs were buried by sediment over millions of years (Devonian to Pleistocene eras) and minerals, primarily silica or calcite, replaced the organic coral structures via permineralization.
Uses & applications
Used for jewelry (cabochons), interior decoration, aquarium decor, and as a popular specimen for fossil collectors.
Geological facts
Agatized coral is the state rock of Florida. It is a unique material where a biological organism has essentially been turned into a gemstone through a process taking roughly 20 to 30 million years.
Field identification & locations
Identified by the distinct pore patterns or 'star' shapes on the surface of the stone, often found in ancient marine beds, riverbanks, and coastal regions. Best found in Florida, Indonesia, and Utah.
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