mineral

Tahitian Pearl

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

Hardness: 2.5–4.5; Color: Black, gray, silver with blue/green overtones; Luster: Pearly/nacreous; Crystal structure: Orthorhombic (aragonite platelets); Specific Gravity: 2.60–2.85.

Hardness: 2
Color: Black, gray, silver with blue/green overtones
Luster: Pearly/nacreous

Identified April 27, 2026More mineral →

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Physical properties

Hardness: 2.5–4.5; Color: Black, gray, silver with blue/green overtones; Luster: Pearly/nacreous; Crystal structure: Orthorhombic (aragonite platelets); Specific Gravity: 2.60–2.85.

Formation & geological history

Formed biologically within the 'Pinctada margaritifera' (black-lipped oyster). It is created as the mollusk deposits layers of nacre around an irritant or implanted bead.

Uses & applications

Primarily used in high-end jewelry (earrings, necklaces, rings) and as highly prized collector items due to their unique dark colors.

Geological facts

Unlike white pearls, Tahitian pearls are naturally dark because of the black lip of the oyster they come from. They are often called 'Black Pearls' but exhibit a vast rainbow of iridescent overtones.

Field identification & locations

Identify by their organic luster and 'cool' touch. In the field, look for the 'tooth test' (a gritty feeling when rubbed against teeth) to distinguish genuine nacre from smooth plastic/glass imitations. Found mostly in French Polynesia.

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