mineral

Black Pearl (Tahitian Style)

Calcium Carbonate (Aragonite) - CaCO3 with Conchiolin

Hardness: 2.5-4.5 Mohs; Color: Black, charcoal, or dark grey with peacock, green, or purple overtones; Luster: Pearly (orient); Crystal Structure: Orthorhombic (microcrystalline); Specific Gravity: 2.60-2.85

Hardness: 2
Luster: Pearly (orient)

Identified May 3, 2026More mineral →

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Physical properties

Formation & geological history

Biogenic formation; produced by the Pinctada margaritifera oyster. Concentric layers of nacre are deposited around an irritant or nucleus over 1-3 years in saltwater environments.

Uses & applications

Primarily used in high-end jewelry (necklaces, earrings, rings) and as a collector's gemstone.

Geological facts

Black pearls are the only pearls that are naturally dark; most 'black pearls' in the market are dyed, but true Tahitian pearls get their color from the specific black-lipped oyster. They are known as the 'Queen of Pearls'.

Field identification & locations

Identify by the 'tooth test' (grittiness against teeth) and checking for natural overtones rather than a flat, dyed surface. Commonly found in the lagoons of French Polynesia (Tahiti).

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