Pearl evaluation

The evaluation indicators of pearls are: shape, skin light, pearl layer thickness, smoothness, and solidity.
(1) shape: ① Positive circle, round pearl: The ball -shaped person is the best shape of the pearl. In ancient times, it was called "walking pearl". The percentage of the diameter difference between the main round beads is less than 1%, the round beads are 1%to 5%, and the nearly round is 5%to 10%. ② non -positive circle pearls: there are different shapes and different shapes. For example, the diameter difference percentage of oval beads is 10%to 20%, and the malformed beads are greater than 20%. There are also flat beads, steamed buns, pear -shaped beads, egg -shaped beads, tear -shaped beads, waist drum -shaped beads, etc. ③ Art Pearl: There are imagined and strange pearls in the deformity beads, such as animals, characters, girls, pandas, fishermen, Guanyin Lotus beads, etc.
(2) skin light: that is pearl, gloss. The thicker the pearl layer, the higher the orderly arrangement of the stone, the stronger the pearl luster, and the more rounded the surface of the pearl is, the better the surrounding objects are good. The pearl layer is mainly based on the stone, and it is better to have a small amount of square stone; the main decoction of the square or the organic matter is large.
(3) Pearl layer thickness: Different species of pearl layers are different. The commercial standards require the pearl layer to reach 0.3 mm and greater than 0.3 mm. It is less than this standard.
(4) Small degree: refers to the degree of smoothness of the pearl surface. Those who can see objects as smooth as mirrors are good products; if they have defects such as cotton, those who affect smoothness are the secondary products.
(5) Revisor: refers to the tightness of the pearl structure. Those with an orderly arrangement of pearl layers and solid beads are the top grade; those with relaxed structure and lighter beads are secondary products; those in the pearl are hollow and fragile.
In order to correctly implement the quality rating, the State Administration of Quality Supervision and Inspection and Quarantine of the National Quality Supervision and Inspection of China issued the Pearl quality rating standard, and implemented nationwide on November 1, 2003 (Table 3-22).
Table 3-22 Pearl rating criteria
The continuation table
∗ The maximum diameter and minimum diameter of pearls to the maximum to the minimum diameter average percentage. (According to Zhou Peiling, 2004)
The color and size are not classified, only as described. The color description of the color is mainly body color, supplemented by color and faint.
The pearl necklace or pairing, set pearl, and its blind date or matching. "Very good" or "A" level, the shape, luster and smoothness are consistent, the color and size are harmonious and beautiful, and the hole is in the middle of the eyes; In -depth, it feels harmonious; the "general" or "C" level, the difference between pearls is more obvious, the hole eyes are slightly crooked and have hair edges.
The pearls are rated by the general rating, which are only divided into "jewelry -level pearls" or "process -grade pearls". The jewelry -level luster is at least "medium" or "C", at least "small flaws" or "c" (9 mm or above pearls are at least "flaws" or "d"), and the thickness of the pearl layer is "thin" or "" D "or above (applicable to nuclear pearls); those who do not meet the above requirements are listed as crafts level pearls.