When you are looking to buy a black Tahitian pearl necklace, the quality and thickness of the nacre is probably the single most important part of the necklace. Nacre is the coating that grows around the pearl while the pearl is formed inside the oyster. The longer a pearl is cultured inside of an oyster, the thicker the nacre will be around the pearl. In Japanese and Chinese pearls, the nacre is produced much slower that in the warmer waters of Tahiti. Experts estimate this production to be about 10 to 15 times slower. The result is that a thickness of 0.5mm in Japanese and Chinese pearls is considered a very thick Nacre. In these pearls, the nacre may consist of up to 30% of the total pearl´s volume.
In contrast, a Tahitian black pearl with a nacre thickness of less than 0.8mm is considered unacceptable and it is not sold locally, nor is it exported for sale. The nacre coating of Tahitian pearl´s can make up to 50% of the pearl´s total volume.
The thickness of a pearl´s nacre is important for a few reasons. It is what protects the pearl, and if the nacre is too thin, the pearl will damage very easily. Furthermore, a thin nacre can wear off quickly, whereas a thick nacre, with proper care, can last for many years. The nacre is also important because it is what gives the pearl its beautiful luster, and that mysterious iridescent look. The thicker the nacre, the greater the iridescent effect.
Now you are aware of how important the nacre thickness is when selecting a Tahitian pearl necklace. However, there are many other factors to consider that are also affect the price and quality. It is important to be aware of these and to select a necklace that suits your purposes.