Where is Fossilized Coral found?
Rugosa or Tabulata coral (likely a type of Favosites or Hexagonaria)
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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
Florida, USA
Known for its agatized coral, particularly from the Tampa Bay area. These are often Miocene in age and exhibit excellent preservation.
Michigan, USA
Famous for 'Petoskey Stones,' which are fossilized Hexagonaria percarinata corals from the Devonian Traverse Group. These are often found on beaches and in glacial deposits.
Indonesia
Produces a wide variety of fossilized corals, often with vibrant colors and intricate patterns, from various geological periods.
Morocco
Known for its Devonian fossiliferous limestones containing numerous Rugosa and Tabulata corals.
Australia
Various localities yield fossilized corals, particularly from Paleozoic and Mesozoic marine deposits.
United Kingdom
Carboniferous limestones in areas like Derbyshire contain well-preserved fossil corals.
Collecting tips
- Geological Maps and Formations. Research geological maps of your area or regions known for marine sedimentary rocks, especially those from the Paleozoic Era. Look for formations described as fossiliferous limestones, shales, or chert beds.
- Coastal and Riverine Environments. In areas where ancient marine sediments are exposed, such as along coastlines, riverbeds, or glacial outwash plains (like in Michigan for Petoskey stones), fossilized corals can be found as 'float' or eroded from their parent rock.
- Quarries and Road Cuts. Limestone quarries and road cuts often expose fresh rock faces where fossils, including corals, can be observed. Always obtain permission before entering private property or active work sites.
- Look for Distinctive Patterns. Fossilized corals are identified by their characteristic internal structures: hexagonal or polygonal patterns (Hexagonaria, Favosites), radial septa (Rugosa), or honeycomb-like structures (Favosites). Polishing a small area can reveal these patterns more clearly.
- Hardness Test. Since fossilized coral is typically replaced by silica, it will be significantly harder than un-fossilized coral or limestone. It should scratch glass and not be scratched by a steel knife (Mohs hardness 6.5-7).
Quick Check
- Color:
- Variable (grays, browns, whites, reds, yellows, blues), often with visible patterns.
- Luster:
- Vitreous to waxy on polished surfaces.
- Streak:
- White (due to chalcedony/quartz).
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