Where is Fossilized Coral found?
Fossilized Scleractinian or Tabulate Coral (likely Hexagonaria percarinata)
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Open the appFossilized Coral occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Fossilized Coral
Michigan, USA
Famous for Petoskey Stones (Hexagonaria percarinata) found in Devonian-age limestones and glacial till, particularly along the shores of Lake Michigan and Lake Huron.
Florida, USA
Known for agatized coral, particularly from the Tampa Bay area, often exhibiting intricate patterns and a range of colors.
Indonesia
Significant source of fossilized coral, often with vibrant colors and diverse coral species, found in various sedimentary deposits.
Morocco
Produces fossilized corals, often embedded in limestone matrices, from various Paleozoic and Mesozoic formations.
Australia
Various locations yield fossilized corals from different geological periods, including silicified specimens.
United Kingdom
Certain Carboniferous and Devonian limestones contain fossilized corals, though silicified specimens suitable for lapidary work are less common than in other regions.
Collecting tips
- Look in Sedimentary Rocks. Focus on areas with ancient marine sedimentary rock outcrops, especially limestones, shales, and sandstones that were deposited in shallow marine environments.
- Search Glacial Till. In regions like Michigan, glacial deposits (till) can contain eroded and transported fossilized corals from underlying bedrock.
- Examine Riverbeds and Beaches. Water erosion can expose and concentrate fossilized corals in riverbeds, stream banks, and along lake and ocean beaches.
- Identify Coral Structures. Look for characteristic coral patterns: hexagonal cells (Hexagonaria), radiating septa, or other colonial growth forms. Weathered surfaces might reveal these patterns more clearly.
- Test Hardness. Silicified coral will be hard (Mohs 6.5-7), scratching glass or steel. This distinguishes it from un-silicified, softer calcium carbonate coral fossils.
- Check for Luster. Polished or wet specimens will often show a waxy to vitreous luster, enhancing the visibility of the internal patterns.
Quick Check
- Color:
- Variable (white, gray, brown, black, pink, red, yellow, blue), often patterned.
- Luster:
- Waxy to vitreous (polished), dull to earthy (unpolished).
- Streak:
- White.
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