2. Gloss: Moist and bright luster is the main source of pearl beauty. Top pearls must have a strong pearl luster. When you identify pearls, you can put them on a white soft cloth and look at the light, and you can see colorful light similar to a rainbow. It is best to have rich layers and strong reflective luster.
3. Shape: Generally, pearls can be divided into the following seven shapes: round, nearly round, oval, button-shaped, drop-shaped, semi-baroque (not completely symmetrical, non-round) and baroque (obviously irregular without obvious symmetry). Large-grained and round pearls are the rarest and most precious, while flat and oval pearl necklaces are cheaper. Baroque, semi-baroque and other shaped pearls, with the blessing of better design, are often very expensive.
4. Size: The measurement unit of pearl size is millimeter. Other factors being equal, the larger the diameter of a pearl, the higher its value. Generally speaking, pearls under 6 mm do not belong to the category of jewelry-grade pearls. 7~9 mm is popular with consumers, and pearls above 10 mm are very rare.
5. Surface quality: As a natural product, pearls will have defects such as growth lines, spots, imprints, pits and spots. Surface quality refers to the nature and quantity of defects and irregular marks on pearls. The fewer defects, the more precious pearls are.
6. nacre: the quality of nacre determines the appearance of pearls. For example, the luster of pearls has a great relationship with the density of pearlite, and the tight texture can give off bright and moving luster. In addition to better skin luster, the thicker the nacre, the central tuberculosis will not be exposed immediately if it is scratched. Therefore, the ideal bead thickness should be about 4.5 mm ~ 5 mm
7. Matching degree: Matching degree is often used to evaluate a string of pearls or jewelry containing more than two pearls. The collocation of "excellent" grade requires that all pearls have the same appearance and the drilling holes are centered.