1, weight (carat). The international standard unit is carat (ct), 1ct = 0.2g, and "minute" is commonly used in China, 1 carat = 100 minute. The price of diamond is directly proportional to its weight, and its value increases geometrically with the increase of weight. At the same time, the same weight of diamonds, due to differences in color, clarity, cut, there will be a price gap.

2. clarity. According to international standards, the classification of clarity grade should be observed from five aspects: the nature, color, size, quantity and location of the contents under a ten-fold magnifying glass. According to China's national inspection standards, diamond clarity can be subdivided into LC, VVS 1, VVS2, VS 1, VS2, SI 1, SI2, P 1, P2, P3*** 10. The higher the clarity of a diamond, the higher its value.

3. color. Diamond color classification refers to the classification of yellow and brown series. Diamond color * * * is divided into 1 1 grades, which are D, E, F, G, H, I, J, K, L, M, N, and D is the whitest diamond grade. In the yellow series, the closer a diamond is to colorless, the higher its value.

4. stop. Diamond cutting refers to the accuracy of its cutting and grinding ratio and the perfection after finishing. Good cutting should reflect the brightness and fire color of the diamond as much as possible, and try to keep the weight of the original stone. The cutting grades of IGI International Gemological Institute are divided into ID (standard), EX (excellent) and VG (very good) G (good) from high to low, and the domestic national inspection is divided into VG (very good) and G (good).

Extended data

Only the "4C" of a diamond determines its value and price, and the "4C" is arranged in the order of importance, so when buying carat diamonds, you should buy loose diamonds in the order of "4C".

Size, because size is easy to see, and the greater the quality of diamonds, the brighter the light. Color, because the whiter the color, the more beautiful and precious the diamond is, and it can be distinguished by the naked eye.

Clarity and cutting are invisible to the naked eye, and it depends on the microscope to see the number of defects and which part of the diamond is defective; Cutting workers now use computers to cut bare diamonds, so that bare diamonds can achieve better refraction surface and more perfect fire color, and there are 57 kinds of classic cutting surfaces, and there will be no bare diamonds like manual cutting before. Therefore, if the price is not much different, it is recommended to choose carat diamonds with high color grade.

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