Tabulate coral is a fossilized colonial coral that lived in prehistoric oceans and has been replaced by silica, usually chalcedony. Collectors prize these specimens for the intricate, honeycomb-like patterns visible on the surface, which are best displayed when polished. They are most commonly found in sedimentary limestone formations where ancient reef systems once thrived.
Is this tabulate coral?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch tabulate coral with a known reference. Tabulate Coral sits at Mohs 5-7, softer than the next harder reference, harder than the previous one.
- 2Name the organismDecide what left the fossil before worrying about the rock. Organism: Extinct corals (class Tabulata). Age: Ordovician to Permian.
- 3Check the preservationPreservation: Calcite skeleton. That controls the weight, the hardness and how the piece takes a polish.
- 4Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 5Match the color rangeCompare against the expected color range: tan, brown, gray, white, black.
Often confused with
Tabulate Coral vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside tabulate coral
Minerals reported to co-occur with tabulate coral. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 5-7
- Density
- 2.6-2.7 g/cm³
- Luster
- Vitreous
- Transparency
- Opaque
- Rarity
- Common
- Uses
- Lapidary, Collector, Decorative
- Host rock
- sedimentary limestone
- Organism
- Extinct corals (class Tabulata)
- Age
- Ordovician to Permian
- Preservation
- Calcite skeleton
Where rockhounds find tabulate coral
Classic worldwide localities
- Florida, USA
- Michigan, USA
- Utah, USA
- Texas, USA
- Indonesia
Field-hunting tip
Where it forms: sedimentary limestone. If you start seeing quartz, calcite, chalcedony in float, you are in the right ground.
More tabulate coral photos
Common questions
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Find tabulate coral on the map
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