Lesson14: Tahitian Black Pearls
1. Introduction
Also known as black-lipped pearls, Tahitian black pearls are named for their primary cultivation region, Tahiti and its surrounding coral reef islands.
2. Origin
Tahitian black pearls are primarily produced in the Society Islands of French Polynesia, especially around Tahiti. These islands account for approximately 95% of global production. The islands are situated between 14° and 23° south latitude, where cooler water temperatures lead to thinner and more beautiful pearl nacre layers. For instance, the island of Mangareva in the Gambier Archipelago offers ideal cultivation conditions due to:
- Wide lagoons,
- Cool water temperatures (southernmost islands of Tahiti), and
- Nutrient-rich waters near Mangareva’s 500-meter volcanic hills.
These factors make this region optimal for black-lipped pearl oyster farming.
3. Mother Oyster
The mother-of-pearl oyster, Pinctada margaritifera, secretes black pigment, creating these unique black pearls.
4. Characteristics
Color
Despite being called “black” pearls, Tahitian pearls come in a variety of hues, including deep black, gray, and brown. They often feature overtones of green, blue, purple, red, and pink. The most prized variety is the “peacock green,” which exhibits iridescent green and red hues.
Size
Tahitian pearls typically range from 8mm to 16mm. Pearls exceeding 18mm are extremely rare and significantly more valuable due to their size.
Shape
These pearls come in various shapes, including:
- Round,
- Oval,
- Baroque,
- Drop, and
- Circled (ringed) shapes.
The circled shape is a distinctive feature of Tahitian pearls, often with excellent luster. Perfectly round pearls are rare and highly valuable.
5. Nacre Thickness
The average cultivation period for Tahitian pearls is 18 months, which allows for thicker nacre layers. Some farms reduce this period to 12 months. The nacre thickness usually ranges between 0.8mm and 2mm. Since the late 1990s, X-ray inspections ensured exports only included pearls with nacre thicker than 0.8mm. Though this regulation ended in 2017, pearls with a nacre thickness of 0.8mm or more are still recommended for durability.