GIA diamond certificate is an internationally accepted diamond appraisal certificate. GIA, the abbreviation of Gemological Institute of America, is the largest and most recognized diamond appraisal institution in the jewelry industry in the United States and even the world, and the inventor of diamond 4C. GIA certificate is equivalent to the ID card of the diamond, which proves the identity of the diamond. GIA diamond classification report and GIA diamond processing are considered as the first gem certificates in the world. Diamonds of all shapes and sizes are sent from all over the world to the college for analysis and classification.
GIA certificate of diamonds in Chinese and English;
Laboratory report: identification certificate number of diamond.
Date: The date when the diamond was identified.
The above is the basic information of the certificate.
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☆ Carat weight: Describe the approximate carat weight of a diamond. Carat is the unit of diamond weight, which is called carat in Chinese. 1 g =5 carats, 1 carat = 100 minutes. GIA is calculated to two decimal places, and the third place is one ninth, for example, 32.89 is 32 points and 32.9 is 33 points;
☆ Clarity grade: the clarity grade of diamonds under 10 times magnifying glass. GIA classifies diamond clarity into FL (completely flawless), IF (internally flawless), VVS 1-VVS2 (extremely imperfect), VS 1-VS2 (slightly flawed), SI 1-SI2-SI3 (flawed) and I/Kloc. Generally speaking, we think that the cost performance is VS 1-VS2, and the collection is IF. SI is ok if it is worn for fun, but in China, we suggest buying a domestic certificate for SI, which costs much less.
☆ Color grade: The color of diamonds is graded. Gem-grade white diamonds start from D color to Z color, and other colors such as pink are called colored diamond, such as fancy pink. Colored diamond also has many levels. White grading is as follows:
Grade D and E, 100, 99 colors, extremely white, D stands for 100% pure white.
F, g, 98, 97 colors, excellent white.
Class h, 96 colors, white.
I, J, 95, 94 colors. It's yellow and white.
K and l grades, 93 and 92 colors, light yellow. In fact, diamonds of this color are worthless.
Below m, yellow and gray. . .
☆ Diamond shape and cutting: mainly describe the shape and cutting of diamonds.
These are the basic parameters of diamonds, which are often referred to as 4C standards.
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Diamond size: the size of a diamond, in millimeters.
Total depth ratio: the ratio of the height of a diamond (round diamond or irregular diamond) to its diameter, that is, the percentage of the height of a diamond to the average diameter of its waist. This ratio depends on the work cut, and the GIA standard is 56.8-62.4% as good-excellent; ;
Table width: the ratio of diamond (round diamond or irregular diamond) table to diameter. The table width is the percentage of the average diameter, and the table size is related to the size of the diamond and whether it will leak light, which is very important. GIA's standard is 52.5%-58.4% excellent. Americans prefer a small desktop, which will make diamonds full of fire. So some people say that the bigger you buy, the bigger it looks, and it looks really big, but if there are fewer diamonds, there will be no fire, and no matter how big it is;
Crown height: the ratio of the crown of a diamond (round or irregular) to its diameter.
Senkaku depth: the ratio of a diamond (round diamond or irregular diamond) to its diameter.
Symmetry: the symmetry grade of a diamond.
Waist thickness: the thickness of the circumference of a diamond.
Undercarriage: the appearance of the cutting surface of the undercarriage.
Polishing grade: the polishing grade of a diamond.
Clarity structure diagram: a display diagram observed under a magnifying glass, which describes the shape of the diamond and the characteristics and position of the inclusions.
Fluorescence: visible light emitted by diamonds under ultraviolet radiation.
Comment: Description of other characteristics of diamonds not mentioned in the report.