Characteristic of Tahitian cultured pearls
Like every gemstone, a pearl requires much classification work before it can be commercialized. On the contrary, pearls are the only gems neither polished nor cut, they keep their natural-born aspect. Following the example of Australian pearls, Tahitian cultured pearls are never polished in order to improve their color or their luster, or worse, to change them. So, Tahitian cultured pearls are the only pearls with such a large range of colors. The commercial appointment, “Cultured Pearl of Tahiti”, is strictly reserved for cultured pearls from graftings made in French Polynesia, on a pearl oyster Pinctada margaritifera, var. cumingui.
Besides, pearls must display a continuous pearly layer covering at least 80% of the surface and cannot reveal its underlying nucleus, even through transparency. Pearls not meeting these criteria will not have the name of “Cultured Pearl of Tahiti”. Criteria to determine the value of a Tahitian cultured pearl are size, measured in diameter, shape, surface quality, luster and color..
Classification of Polynesian pearls
Tahitian cultured pearls are classified from millimeter to millimeter between 8 and 16 mm, by sorting through sieves. Three basic shapes exist : Rounds / Semi-rounds , Drops, and Baroques. The first ones are spherical and uncommon. Drops are symmetrical, and correspond with pear, drop and oval shapes. Baroques pearls are asymmetrical or display concentric circles around their surface, which gave them the name of Circled pearls.
The quality changes according to the purity of the surface.
International nomenclature defines four basic qualities :
- AAAA pearls are exceptional and present a flawless surface.
- AAA pearls are perfect, but may present a few confined imperfections.
- AA pearls may present imperfections over at most 60% of its surface.
- A pearls present many imperfections all over their surface.
The most important indication of a pearl’s quality is the luster. Key aspect of nacre, it represents an important difference from many other gems. In Polynesia, a similar classification is standard, but with different denomination. There are pearls of quality A, B, C or D, with the following equivalencies :
- Top gem equals to AAAA
- A/B equals to AAA
- C equals to AA
- D equals to A
Natural colors of Tahitian Pearls
Tahitian cultured pearls feature the greatest and most diversified natural colors palette among all the categories of cultured pearls. Their natural colors are their chief assets and form a real added value. Generally, Tahitian cultured pearls feature a main color tinted with several color shades. The most common colors are black, grey, blue, green, purple and brown. Color shades may look pink, blue, golden, silvered. These color tones may vary from very light to very dark.
The life span of a cultured pearl is determined by the thickness of the nacre layer. If it is thick enough and the pearl is well-maintained, you will enjoy its beauty for your whole life. On the contrary, if the layer is thin and the pearl overlooked, nacre will deteriorate, eventually revealing the underlying nucleus. The Government of French Polynesia has imposed a minimal thickness of 0.8mm. Every pearl which does not meet this criterion shall be destroyed.