CLEANING :
Before anything else, pearls have to be cleaned to remove all the dust and mucus which have dry on their surface once outside the oyster. This is done in a tumbler with walnut or bamboo pieces and might last a few hours.
GRADING :
As soon as the pearls are clean and dry, they are ready to be sorted and classified. Sorting the pearls is quite a long process and unlike Diamonds, there is no world standard grading system for pearls. Even if the nomenclature vary between country and official organizations, pearl value is based on five important criterias which are : size, shape, surface, luster and color.
From our practical experience, the pearls are first classified in a defined order by shape, quality and size.
SHAPE
There are three typical Shapes:
_Round / Semi-round (R/SR)
_Drop/Oval/Button (DR)
_Baroque (B/CL)
R/SR are spherical and among the rarest. DR pearls have symmetrical shapes such as pear, drop, oval. B/CL pearls concern asymmetrical pearls or symmetrical pearls with rings around their surface called also circled.
QUALITY
The quality will depend on the purity of the surface. It consists of 4 grades defined by the following nomenclature :
- Completely clean: Top Gem
The surface of the pearl has no blemishes all around. The surface is smooth, even and uniform. There is no unevenness in the layers of the nacre. High luster
- Almost clean: AAA
The surface has one or several small blemishes on one side of the pearl. When looking from the most advantageous side, the pearl shows a clean surface. The flaws will not be visible when the pearl is set into jewellery. Minor irregularities in the layers of the nacre are accepted. High or excellent luster
- Slightly spotted: AA
The pearl has blemishes all around the surface. The blemishes are minor and are not affecting the overall appearance or uniformity of the pearl. The spots will be visible when the pearl is set in jewellery. There are no major damages to the pearl. Shark- or Orange skin and disturbances in nacre layers are acceptable as long as they are not in the form of cracks and major blemishes. Good luster
- Important spots : A
The pearl has visible, strong blemishes. The blemishes cannot be hidden when the pearl is set into jewellery. Good or medium luster
More damaged pearls are not allowed to be sale.
SIZE
Tahitian Cultured Pearls are classified millimeter by millimeter, between 8 mm and 16 mm or more through sieves. It is possible to find bigger size in the tahitian pearls but up to 14mm, good quality pearls are very rare.
COLOR
Tahitian Cultured Pearls have the largest and the most diverse palette of natural colours of all types of cultured pearls. Its natural colours are its main strengths and make a valuable difference. Most of the time, Tahitian cultured pearls have a basic colour enriched with one or more overtones. The most common colours are black, grey and green. The overtones are pink, blue, gold, silver, and purple. These colour may also vary from the lightest to the darkest.
THE QUALITY OF THE NACRE
The thickness of the layer of mother of pearl, nacre, determines the lifespan of a cultured pearl. If the layer is thick enough and you reasonably take care of the pearl, you will fill a pearl of beauty for a lifetime. However, if the layer is thin and the pearl neglected, the mother of pearl will deteriorate until showing the nucleus. The French Polynesian Government has imposed a minimum required thickness of 0.8 mm controlled by X-ray. All the pearls which do not meet this criteria, are destroyed.
