sedimentary
Fossilized Coral
Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)
Hardness: 3-4 (calcite) to 7 (agatized); Color: white, tan, pinkish; Luster: dull to waxy; Structure: distinct honeycomb or septa patterns; Cleavage: none.
- Hardness
- 3-4 (calcite) to 7 (agatized)
- Color
- white, tan, pinkish
- Luster
- dull to waxy
Identified More sedimentary →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3-4 (calcite) to 7 (agatized); Color: white, tan, pinkish; Luster: dull to waxy; Structure: distinct honeycomb or septa patterns; Cleavage: none.
Formation & geological history
Formed through the fossilization of marine coral colonies. Over millions of years, the organic coral skeleton is replaced by minerals, often in shallow marine environments during the Paleozoic to Cenozoic eras.
Uses & applications
Used primarily for jewelry (cabochons), ornamental decoration, aquarium decor, and as educational geological specimens.
Geological facts
Agatized coral is the state rock of Florida. These fossils can be hundreds of millions of years old and represent ancient reef systems that are now on dry land due to shifting plates.
Field identification & locations
Identify by looking for repeating geometric 'star' or 'flower' patterns (the corallites) on the surface of a stony rock. Frequently found in coastal regions or areas that were ancient seabeds.
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Chert Breccia
Brecciated Chert (Microcrystalline Silica)
sedimentary
Sandstone Grain
Clastic Sedimentary Rock Grain (SiO2 dominated)
sedimentary
Shale or Slaty Mudstone
Argillaceous sedimentary rock
sedimentary
Sandstone
Arenite
sedimentary