fossil

Fossil oyster shell fragment

Fossilized oyster (Ostreidae), composed mainly of calcite (CaCO₃)

AI-generated identification · may be incorrect

Cream-white, irregular layered shell with gray-brown matrix and fractures; pearly to dull luster, low birefringence, and excellent cleavage in calcite. Hardness is about 3 Mohs; specific gravity is approximately 2.7.

Identified August 19, 2026More fossil →

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Physical properties

Formation & geological history

A marine bivalve shell was buried in sediment and partially mineralized or preserved during diagenesis, commonly in Cenozoic to Mesozoic marine limestone deposits. The layered, strongly curved shell texture is characteristic of oysters.

Uses & applications

Primarily a collectible or educational fossil; comparable shell material may be used decoratively, while crushed fossil shell can serve as calcium-rich aggregate or soil amendment.

Geological facts

Oyster shells are built from calcite layers and commonly preserve growth lines, attachment scars, and boring traces from marine organisms.

Field identification & locations

Identify it by its curved laminated shell, irregular valve shape, and calcite reaction to dilute hydrochloric acid or vinegar; likely sources include coastal marine sedimentary formations worldwide. Avoid acid testing if preservation or surface appearance must be protected.