Where is Fossil Coral found?
Fossilized Rugose or Tabulate Coral
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Open the appFossil 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 Fossil Coral
Florida, USA
Known for its agatized coral, particularly the 'Florida Agatized Coral' which is the state stone. Found in Miocene-Pliocene deposits, often in riverbeds and coastal areas.
Indonesia (Sumatra)
Produces large and beautifully patterned fossil corals, often with vibrant colors, from Cenozoic deposits.
Morocco
Known for Paleozoic (Devonian) rugose and tabulate corals, often found in limestone formations.
Utah, USA
Various Paleozoic coral fossils, some silicified, can be found in marine sedimentary layers.
Michigan, USA
The 'Petoskey Stone' is a well-known fossil coral (Hexagonaria percarinata) from Devonian deposits, often found on beaches and in glacial till.
Australia
Various locations yield fossil corals, including silicified specimens.
United Kingdom
Paleozoic coral fossils are found in various limestone formations.
Collecting tips
- Look in Sedimentary Rocks. Focus on areas with marine sedimentary rock outcrops, especially limestones, shales, and sandstones that indicate ancient shallow marine environments.
- Check Riverbeds and Beaches. In areas known for fossil coral, riverbeds, gravel pits, and beaches (especially those with glacial till) can be good places to find water-worn specimens.
- Identify Coral Patterns. Look for distinctive cellular, radial, or honeycomb patterns characteristic of coral polyps. Even if the color is muted, the structure can be diagnostic.
- Acid Test (Caution). While the original coral was calcium carbonate, silicified coral will not react with dilute hydrochloric acid. If it fizzes, it's likely still limestone with coral impressions, not fossil coral (agatized).
- Examine for Luster. Silicified coral, especially when wet or polished, will often exhibit a waxy to vitreous luster, distinct from the duller appearance of un-silicified limestone.
Quick Check
- Color:
- Variable, often earthy tones with distinct coral patterns.
- Luster:
- Waxy to vitreous (polished), dull to earthy (unpolished).
- Streak:
- White (due to chalcedony/quartz).
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