TAHITIAN CULTURED PEARLS
Tahitian Cultured Pearls are pearl concretions that are secreted inside the black-lipped Pinctada Margaritifera species of pearl oysters cultivated mainly in the lagoons of French Polynesia. They consist of thick pearly layers containing organic substances and calcium carbonate in the form of aragonite.
In French Polynesia, the trade designation "Tahitian Cultured Pearl" is reserved exclusively for cultured pearls obtained from a grafting of the locally cultivated Pinctada Margaritifera, variety cumingi pearl oyster. Such pearls have a continuous pearly layer over at least 80% of their surface and do not reveal either the underlying nucleus.
Tahitian Cultured Pearls are classified according to their diameter, luster, shape, surface purity and color.
Pearls are classified from millimeter to millimeter and measured by the shortest diameter, which generally ranges between 8 and 14mm. This is done by sorting them through sieves. Some pearls reach 16mm and very exceptionally 18mm. To date, the record diameter for a round pearl is 21mm, 24,6mm for a semi-round, 26,95mm for a baroque pearl (Exhibited in The Robert Wan Museum of The Pearl).
This is the quality of the light reflections from the pearl's surface. Pearls are said to have high, or very high, luster when the reflections are bright and sharp. When the light reflections are weak and fuzzy (or diffused), the pearls are described as dull. The Tahitian Cultured Pearl rivals anything grown in Japan for the sharpness and intensity of reflected light from a pearl's surface. In fact, pearls from French Polynesia often possess such a mirror-like finish and radiant brilliance that their overall appearance is likened to that of very shiny metallic objects, such as ball bearings.
The only problem with such an analogy is that it suggests a cold, steely beauty. In reality, lustrous Tahiti Cultured Pearls have warmth to them--even when their surfaces gleam as brightly as a dress shoe.
Regardless, the lustre of the Tahitian Cultured Pearls is just like their color--all natural.
Four basic shapes are defined at the production stage:
1. Round and semi-round
4. Ringed or circled
ROUND & SEMI-ROUND
RINGED OR CIRCLED
For some jewelery makers, shape is purely a design element, be it the sensuous curves of the drop or the flowing free-form lines of many baroque shapes. For such artists, all shapes that inspire them share aesthetic equality.
Most designers agree it is difficult to favor one kind of shape over another. A New York designer once said: "A pearl that looks homely seen loose will be transformed into a thing of beauty if placed in the right setting."
This is determined by observing the special features of the pearl's surface and luster. But nacre thickness, color, shape and size also judge quality.
For reasons best understood by psychologists, pearl dealers talk about the degree to which a pearl's skin is free of blemish as "spotting", a very negative term for a very common pearl feature.
Tahitian cultured pearl farmers generally use four ratings for surface quality: A, B, C and D. Pearl dealers prefer the neutral term "surface" as a way of discussing--or even rating--the presence or absence of imperfections in pearls. In this regard, it is the pearl word equivalent of "clarity".
This affects the durability and sometimes the beauty of a Tahitian cultured pearl.If a cultured pearl starts off with a thick coating of nacre (and gets reasonable care), its beauty will last a life time.
If, however, the pearl has a thin nacre coating (or is carelessly treated), its nacre will soon wear away, exposing the nucleus.
The French Polynesian Government has set up a minimum nacre thickness of 0,8mm to the Tahitian Cultured Pearl. All pearls showing less than 0,8mm thickness are banned for marketing and destroyed.