The Tahitian pearls need to be very carefully controlled by assessing their quality so that no undesirable type of pearl can go to market. The thickness of the nacre layer must be more than 0.8 mm which can be measured by X-ray.
Those saltwater pearls which has a minimum amount of defect will be considered as more expensive. Also, by using any gemstone too its imperfection can be concealed.
Following are few criteria used for determining the quality of pearls.
Pearls that are in perfectly round shape are considered to be the best, however, any semi-round with diameter variation of about 2 to 5% are also accepted.
Few pearls are also available in button, drop, oval or pear-shaped which are called semi-baroque pearls.
If the surface has got the least amount of defect then it will be considered as the most expensive pearl. Any A-grade pearl may have a maximum 10% imperfection while D-grade can have more than 50% imperfection.
Any very large pearls can be formed due to repeated grafting. It will be very unusual if you can get pearl whose diameter will be more than 12 mm. They are rare pearls which will be much more expensive than any standard pearl.
4. Colour shade
White is the most commonly available color and besides that, you can get blue, green, coppery and cherry colors too. Beautiful color with luster will be considered expensive.
Luster means an ability to reflect lights. High luster pearls are the most reflective and will be considered more exclusive. Even medium luster pearls are also considered by many customers.
Orient can be considered as specific iridescent sheen which creates the imprint of light passing over the nacre. This light can be broken up to create multi-colored iridescent colors almost like a rainbow.
Such effect can rarely be seen on pearls that normally have an iridescent sheen and also dominant body color.
Matching all pearls of same iridescent sheen and color can be a very complicated affair. If all the sets of pearls are elegantly matched with each other then it can really increase the value of the jewelry.