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Tahitian Pearls

How to determine the quality of a Tahitian black Pearl

How can you determine the value of a gem and, more precisely, that of Tahitian black pearls? There are several criteria that Perleria de Tahiti and the House of Georgia H. use to determine a pearl’s quality. The following article provides you with extensive details about the process and methods used.

The quality of Tahitian black pearls

Prime breeding conditions for the pearl oysters

Tahitian black pearls have a wide array of surface qualities. In order to understand them, it is important to remember that this gem is natural and grows in a specific environment, which greatly influences its characteristics, appearance and therefore its value.

Nature’s unpredictability

It is paramount that the Pinctada margaritifera oyster in which the pearl develops is in perfect health. During the cultivation process, which lasts about 18 months, the pearl sack is perpetually transforming since it is constantly growing with the pearl it is secreting.
Any anomaly within this live system that occurs during this period will have negative repercussions on the final quality of the Tahitian black pearl growing within the oyster. It will cause the secretions to be laid improperly, creating imperfections on the pearl’s surface.

The Tahitian black pearl’s surface

The surface of the Tahitian pearl is composed of countless layers of nacre, which are gradually deposited around the nucleus that was grafted into the oyster.
Since this is a natural process each pearl is different. The first step in assessing the quality of a Tahitian black pearl is to inspect it with the naked eye, making note of the following two characteristics: the condition of the surface and the luster.

The first point of comparison

One should check whether or not the pearl’s surface is smooth or has any imperfections. These are the result of natural phenomena and can alter the pearl’s layered surface. Be careful to look for scratches, cracks, divots, bumps, protrusions, growths, deposits of organic material, etc. It should be noted that very few pearls have completely perfect and flawless surfaces. If a pearl does have a perfect surface it is considered to be a top-quality gem.

The more perfect the pearl’s surface is, the more unique and rare it is and the higher its market value. A Tahitian pearl’s quality is also determined by its size, shape and color.

Regulations for the grading system and nacre thickness

Minimum requirement

The French Polynesian government works hand-in-hand with the producers to promote the Tahitian black pearl. What sets Tahitian pearls apart is that the government controls the pearls. Before they can be legally exported the quality of the nacre has to pass several inspections. The pearls are first visually inspected for nacre quality and surface purity. The pearls that pass this test then go on to be x-rayed. During this step of the process each individual pearl is checked to make sure that the nacre thickness is a minimum of 0.8 mm. If the pearls pass this final inspection they are legally available for sale.

Different categories of quality

French Polynesia employs a grading system to determine the quality of Tahitian black pearls. It is important to note that the system that is used on the international market is different. The House of Georgia H. / Perleria de Tahiti uses a personalized and simplified classification system that uses elements from both the Tahitian and international system.

Gem quality

This is the finest Tahitian pearl grade available. Pearls without any imperfections and excellent luster fall into this category.

Grade A

Pearls can be placed in this category if 90% their surfaces are free of imperfections. The remaining 10% must have very few, slight defects. Their luster is very good.

Grade B

70 % of the surface must be free of imperfections and there can be one or two obvious defects. The lustre is good.

Grade C

Flawless on at least 40% of the pearl’s surface. The luster is medium.

Grade D

At least 60% of the pearl’s surface will exhibit flaws. Luster is poor.

Nacre thickness

The nacre’s thickness is the last criterion used to evaluate the quality of a pearl. This factor affects the durability and sometimes the beauty of the gem. Tahitian pearls are known for having thick nacre due to the pearl’s long gestation period within the oyster. Pearls that do not pass the x-ray test to determine nacre thickness are destroyed.

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