The quality evaluation method of pearls can be said to be very systematic and scientific, just like the 4C grading of diamonds. The international evaluation of pearl quality mainly includes the following aspects: 色, 光沢, 透明性, テクスチャ, 形, サイズ, 等. In the case of cultured beads, there is also the problem of the thickness of the bead layer.
1. colour
The colors of pearls mainly include body color and accompanying color.
The best body colors are pure white and black. The other colors are mainly milky white, ピンク, 金, dark green, dark blue, dark gray and purple. Other colors are inferior.
White pearls are best with pink color, black pearls are best with peacock green, peacock blue and peacock purple are also very good, if there are several accompanying colors at the same time, it is even more rare.
2. 光沢
A good quality pearl should have a high-quality luster.
3. 透明性
Most high-quality pearls are translucent, but with the loss of moisture, the transparency will become worse, and they will look deep and dense.
4. テクスチャ
There are often some small pits, 傷, wrinkles, 等. on the surface of a pearl. These pits will affect its beauty. したがって, a pearl without flaws is of course the best.
5. 形
An ideal pearl should be round, but apart from nucleated cultured pearls, it is difficult to get round pearls. The common shapes are oval, drop shape, button shape, as long as the shape is beautiful and symmetrical, it is also very good.
6. サイズ
The size of the pearl should be divided into two aspects: quality and size.
Pearls have a special quality unit-grains (also called “pearl centimeters”). 1 pearl grain = o. 05 g, it can be seen that the gap between each grain is very small. When evaluating the value of pearls, first give a quality grade according to the first five points, and then consider its quality. There is a standard of “seven-point bead and eight-point treasure” in the folk, つまり, a pearl diameter of 9 mm is already very good, the heavier the better.
7. Artificial processing
Pearls are generally processed for jewelry. Punching and drilling are the most common, which is also very particular. If the hole is not in the center of the pearl, the pearl will deflect to one side after passing through the rope. It is almost impossible to make another hole, so the quality of the hole will directly affect the value of the pearl.