The quality and value of diamonds are evaluated from four aspects: lathe work, color, clarity and weight, which is called 4C. Generally speaking, the greater the diamond score, the whiter the color and the higher the purity, that is, the less inclusions, the better the lathe work (which can make the diamond strengthen the light refraction and better the temperature). Generally speaking, the better the quality, the higher the price.

Color (color)

Diamonds have many natural colors, from precious colorless (white after cutting), rare light blue and pink to common light yellow. The more transparent and colorless, the more white can penetrate, and the richer the color after refraction and dispersion.

The grading of diamond color is determined by technicians repeatedly comparing the diamond to be graded with the standard color colorimetric stone in the grading environment of professional laboratories.

The whitest diamond is set to D (that is, starting from the first letter of the diamond). The color of diamonds is divided into 1 1 grades, which are D, E, F, G, H, I, J, K, L, M and N in turn.

Clarity (clarity)

Clarity includes two parts, namely, the original defects inside the gem and the defects caused to the diamond surface during processing. The clarity is not easy to distinguish with the naked eye, so it is best to choose an authoritative diamond for the first time. General appraisers will observe the results through a magnifying glass of 10 times.

FL (flawless), a completely flawless diamond, without any flaws inside or outside. This level allows additional facets in the pavilion, but these facets are not visible on the table; Visible natural primary facet or cleavage plane, its size does not exceed the waist width, or does not make the waist round; There are small spots inside, because it is colorless and does not affect the perspective.

If (there is no defect inside), the internal cleanliness level. There is no flaw inside, but there is a little flaw on the surface.

VVS 1 (very, very thin) is a very, very subtle level of internal defects. There are tiny flaws, which can only be observed from the pavilion or there are small flaws on the surface. The difference between VVS2 and VVS 1 is that VVS2 has tiny flocs (basically no defects inside).

VS 1 or VS2 (very slightly contained), which belongs to slight defect level. You can see very tiny flaws, and you can clearly see the size and position. The difference between VS 1 and VS2 is that VS2 may have tiny flocs and feathers.

SI 1 and SI2 (slightly contained), slightly defective. Defects can be seen under a magnifying glass of ten times.

I 1, I2, I3 (imperfect), not clean. You can clearly see the flaws, and sometimes you can clearly see the obvious cleavage.

Weight (carat)

The weight of diamonds is measured in carats. As a unit of weight, "carat" originated from the seed of a carob tree along the Mediterranean coast of Europe. There is a strange phenomenon in carob trees. No matter where it grows, it bears the same weight of nuts. Historically, this fruit has been used as a weight to measure weight. Over time, it has become a unit of weight for weighing precious and subtle substances. 1907 is an internationally recognized unit of gem measurement, which is still in use today.

1 carat = 0.2g Because diamonds are precious and rare, they need to be further subdivided in measurement, so 1 carat is divided into 100. For example, a diamond weighing 0. 18 carats can be called 18 cents.

Colors are divided into D E F G H I J K L M N (n). Generally speaking, you can pass if you can reach H. In fact, compared with ordinary consumers, the meaning of color is not great. After all, even experts can't see clearly without props.

Cut (cut)

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).

In China, ordinary people generally measure the value of diamonds by weight. Actually, it is not scientific. Because small diamonds are very popular in China. Therefore, the more popular concept is high-quality diamonds. High-quality and bright diamonds generally grasp the three principles of 4C: clarity, color and cut, and the three standards must reach a certain standard at the same time.