How to Buy Black Pearls

Black pearls come from the Pacific waters around Tahiti. These pearls, also called Tahitian pearls, originate in black-lipped oysters (Pinctada margaritifera). A pearl results when an irritant appears inside an oyster; the oyster secrets a substance called nacre to coat the irritant. If the irritant appears in the oyster by accident, the oyster produces a natural pearl. Irritants placed in the oyster by man result in cultured pearls.

Difficulty: Easy

Instructions

1. Decide on a color. Tahitian black pearls come in a wide range of colors, not only black, although that is the most popular color. Black pearls may be gray, cream, blue, turquoise, pink or gold. The rarest, and therefore the most expensive, color for black pearls is eggplant, or deep purple, and peacock green.

2. Look at the size. Pearls from the black-lipped oyster tend to be larger than that of other oysters, such as Japanese oysters. Other oysters' average range is from 4 to 7 millimeters. Black pearls start at 8 millimeters and average about 10 to 11 millimeters. Larger pearls are rarer and more valuable.

3. Rotate the pearl. This will show the orient, or iridescent overtone, of the pearl, which results when light plays through the layers of nacre. It should be a shimmer of colors and varies from pearl to pearl. With black Tahitian pearls, the greenish-black and blue orient is preferred. Higher quality black pearls have a strong orient.

4. Examine the luster. Luster is the mirror effect of the pearl and comes from the thickness of the nacre. The thicker the nacre layers, the higher the reflective, or mirror, effect, which means a better pearl. Nacre that is too thin looks dull or fuzzy; it may also wear off quickly.

5. Determine the shape. The most prized shape is perfectly round. Other shapes, such as baroque and pear, are popular. Personal taste dictates the preference in shape.

6. Check the surface. Regardless of the shape style, the pearl surface should be smooth, with no pitting or chips. Since pearls are a creation of nature, variations occur, but the smoother the surface, the more desirable the pearl.

Tips & Warnings

• Pearl grading has not been standardized and therefore should be used as a guideline only. Pearl grades are AAA (extra fine) to BB (commercial).
• Some pearls are dyed black; they are difficult for the consumer to spot. Dyed black pearls usually look different under ultra-violet light, and imperfections in the coloring might be seen under strong magnification. Buy pearls from a trusted source to ensure that the black pearls are actually Tahitian black pearls.