Rock Identifier
Fossil-bearing limestone (probable) (Limestone, chiefly calcite (CaCO₃), with a visible spiral fossil that may be a gastropod) — fossil
fossil

Fossil-bearing limestone (probable)

Limestone, chiefly calcite (CaCO₃), with a visible spiral fossil that may be a gastropod

AI-generated identification · may be incorrect

Dark gray-brown, fine-grained, dull carbonate rock with embedded shell-like forms; calcite hardness is 3 Mohs, but rock hardness varies. The spiral feature is consistent with a fossil shell, though the image is not detailed enough to confirm its identity.

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Physical properties

Dark gray-brown, fine-grained, dull carbonate rock with embedded shell-like forms; calcite hardness is 3 Mohs, but rock hardness varies. The spiral feature is consistent with a fossil shell, though the image is not detailed enough to confirm its identity.

Formation & geological history

Likely formed from carbonate mud and shell material deposited in a marine setting, then lithified; the rock’s age cannot be determined from the photo. The reported Johor-area location makes marine sedimentary rock plausible.

Uses & applications

Limestone is used for cement, aggregate, and building stone; fossil-bearing pieces are mainly collected or displayed.

Geological facts

Limestone commonly preserves shells and other marine fossils, especially where sediment rapidly buried them.

Field identification & locations

Look for fizzing with dilute acid (a limestone clue) and repeated shell structure; avoid scratching or acid-testing the apparent fossil. Nearby geological material is more likely sedimentary than a rare gemstone.

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Other fossil specimens

Probable fossil-bearing rock or mineral concretion (Unidentified carbonate-rich concretion with a possible fossil inclusion) — fossil

Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

fossil
Likely fossil oyster shell (Fossilized bivalve shell; exact species cannot be identified from the image) — fossil

Likely fossil oyster shell

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

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

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil
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
Fossil oyster shell (Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)) — fossil

Fossil oyster shell

Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)

fossil
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