First, the clarity FL is flawless. If the interior is perfect, the surface is slightly defective VVS 1. VVS2 contains tiny inclusions (tiny defects invisible to the naked eye) VS 1. VS2。 Contains tiny inclusions (tiny defects invisible to naked eyes) SI 1. SI2。 Small inclusions (invisible to the naked eye) i 1. I2.i3. G, H, I and J belong to the near colorless range; K, l and m are yellowish; Below N, diamonds are rated as light yellow-diamonds are known as the "king of gems" in the world because of their highest hardness, crystal clear texture and dazzling features. It symbolizes success, elegance, loyalty, eternity and innocence, so it is deeply loved by people. At present, diamond is the most traded gem in the world jewelry trade. Since the advent of portable detection instruments such as thermal conductivity meter, it has become a very simple matter to identify the authenticity of diamonds, but how to evaluate the quality of a diamond has become the main problem in diamond trade. According to the latest national standard GB/T 16554- 1996, there are four factors to evaluate the diamond grade, namely, color, clarity, cut and carat weight. These four factors are also called "4C" criteria. "4C" is the first letter C in four English terms: color, clarity, cut and carat weight. 4C is an indispensable comprehensive factor to evaluate the quality of a diamond, and it is also a measure for consumers to judge the value of a diamond. There are all kinds of diamonds in the jewelry market, including pure natural diamonds and irradiated and filled diamonds. There are white diamonds (actually colorless with white characters on a white background), yellow diamonds, and red, green, blue and orange colored diamond. From the shape, there are standard round diamonds, as well as heart-shaped, oval and pear-shaped diamonds. The most common diamonds in the market are white (colorless) standard round diamonds, so in the "4C" standard, the classification of diamond color, clarity and carat weight only refers to the classification of natural white (colorless) to light yellow (brown, gray) series polished diamonds with carat weight greater than 0.2, while the cutting classification only refers to standard round diamonds or white (colorless) to light yellow (. The "4C" standard is not applicable to the classification of colored diamonds, irradiated diamonds and filled diamonds. In the "4C" standard, the color of diamonds is divided into 12 grades. The grading method is: the pure colorless diamond is defined as the highest color pole-extremely white, 100 color, which is expressed by D, and can also be written as D( 100). With the increase of the yellow component of diamonds, the color grades gradually decreased to E(99), F(9), G(97) and H(96). In the diamond appraisal certificate, the color grade is usually expressed only by English letters. When the color grade is lower than n, it is generally considered that the diamond is no longer suitable for cooperative jewelry. The color grading of diamonds is determined by professional technicians who compare the diamonds to be graded with standard colorimetric stones repeatedly in the grading environment of specified standards. Or use a colorimeter to scan the diamonds to be classified in the visible range, and then determine them through a series of technical analysis and processing; The purity of a diamond is its purity. The higher the purity of a diamond, the less impurities, defects or flaws there are, and vice versa. Objectively speaking, flawless diamonds are rare. According to the standard, the internal and surface defects of graded diamonds were carefully observed with a magnifying glass of 10 times. Under this condition, the clarity of diamonds can be divided into five grades: flawless LC, extremely defective VVS, slightly defective VS, defective SI and severely defective P, and further subdivided into sub-grades 10, namely LC, VVS 1, VVS2, SI 1, SI2 and P. Diamond cutting refers to the proportion and decoration degree of cut diamonds, which is an index directly influenced by human factors in 4C standard. The brilliance of diamond is attributed to its unique high refractive index and high dispersion (commonly known as "fire color &; Rdquo, only excellent and proportional cutters can fully reflect the incident light and show the unique luster, brilliance and flash of diamonds to the maximum extent. If the cutting is rough and out of proportion, there will be "light leakage". Even if the color of the diamond is good and the cleanliness is good, it is impossible to have a good light, and its value is still low. The simple way for consumers to judge the cutting quality is to pick up the diamond and stare at the shining light on the top of the diamond. If there are not many colors, the cutting is not ideal. According to the standard, cutting is divided into three grades: very good, good and average; The unit of mass (weight) of diamonds is grams, but "carat" is still used as the unit of mass (weight) of diamonds in international diamond trade. 1 carat = 200mg = 0.2g. 1 carat is divided into 100 parts, and each part is called10.8. When the color pole, clarity and cutting conditions are similar, with the increase of diamond weight, its value increases geometrically. Consumers should choose diamonds of suitable size according to their hobbies and actual conditions. The Belgian Diamond High Council is officially recognized as representing the Belgian diamond trading industry. Its headquarters is located in Antwerp, the world diamond center. HRD diamond color certificate focuses on the detailed characteristics that determine the value of colored diamond, such as color description, color design and luminescence. It plays an important role in detecting whether diamonds are natural colored diamond or imitation diamonds. Diamond certificate number (laboratory report: date of diamond identification certificate number): date of diamond identification; Diamond shape and cutting: mainly describe the shape and cutting method of diamond; Diamond size and carat weight, in millimeters. Describe the total depth of diamond carat weight, accurate to about one percent: table width height of diamond (round or colored diamond) relative to diameter: table height of diamond (round or colored diamond) relative to diameter: height of diamond (round or colored diamond) relative to diameter. The depth of the pavilion in the crown: the symmetry of the diamond (round or colored diamond) pavilion relative to the diameter: the symmetry grade of the diamond; Ring thickness: the thickness of diamond circumference; Sharpening: Polishing of the bottom sharp surface. Clarity grade of polished diamond: the clarity grade of diamond under 10 times magnifying glass. Clarity structure diagram: a display diagram observed under a magnifying glass, which describes the shape of a diamond and the characteristics and position of its inclusions. Color grade: fluorescence of diamond: visible light emitted by diamond under ultraviolet light Comments: Yes.