mineraloid / biogenic specimen

Shell Cameo

Cypraecassis rufa (Bullmouth Queen Helmet Shell)

Hardness: 3-4 (Mohs scale), Color: layers of cream/white over orange or brownish-pink background, Luster: Vitreous to pearly, Composition: Calcium Carbonate (Aragonite/Calcite), No crystal structure (amorphous/biogenic)

Identified March 15, 2026More mineraloid / biogenic specimen →

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Physical properties

Formation & geological history

Formed through the biological growth of sea mollusks in warm tropical waters. The layered structure of the shell allows artisans to carve through different colored layers to create 3D relief images.

Uses & applications

Predominantly used in jewelry, decorative arts, and collectors' antiques. This specific specimen is a brooch or pendant featuring a miniature 'Grand Tour' style landscape carving.

Geological facts

Cameo carving dates back to ancient Greece and Rome. Shell cameos became popular in the Victorian era as souvenirs from Italy. Unlike stone cameos (often agate), shell cameos are softer and can be carved with hand tools.

Field identification & locations

Identify by looking for distinct layers of color and fine carving marks under magnification. Authentic shells often show natural growth lines or slight curves on the back. Commonly found in vintage stores and estate sales, originally sourced from the Mediterranean or Indian Ocean.

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