Rock Identifier
Fossil Coral (Rugosa or Scleractinia (Agatized Coral)) — fossil
fossil

Fossil Coral

Rugosa or Scleractinia (Agatized Coral)

AI-generated identification · may be incorrect

Hardness of 6.5 to 7 on the Mohs scale, yellowish-brown to tan color, waxy to vitreous luster, microcrystalline quartz structure.

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Physical properties

Hardness of 6.5 to 7 on the Mohs scale, yellowish-brown to tan color, waxy to vitreous luster, microcrystalline quartz structure.

Formation & geological history

Formed when ancient coral colonies were buried by sediment and their original skeletal structures were gradually replaced by silica-rich groundwater over millions of years.

Uses & applications

Used primarily in lapidary arts, wire-wrapped jewelry, and by fossil or mineral collectors.

Geological facts

Many fossil coral specimens display distinctive honeycomb or star-like patterns representing the original coral polyps.

Field identification & locations

Identify by its unique cellular or branching patterns on the surface; commonly found in limestone deposits and ancient seabed regions.

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Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

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Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

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Crinoid Stem Fossil in Matrix (Phylum Echinodermata, Class Crinoidea) — fossil

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

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Fossiliferous limestone (likely a crinoidal or shell-fragment limestone) (Bioclastic limestone, composed chiefly of calcite (CaCO₃)) — sedimentary

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

sedimentary
Porous limestone pebble (Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image) — sedimentary

Porous limestone pebble

Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image

sedimentary
Weathered fossil bone fragment (identification uncertain) (Fossilized bone; exact taxon and mineral composition cannot be determined from the image) — fossil

Weathered fossil bone fragment (identification uncertain)

Fossilized bone; exact taxon and mineral composition cannot be determined from the image

fossil