1. international general certificate: issued by international authoritative diamond appraisal institutions, such as GIA (American Gemological Institute) and IGI (International Gemological Institute). These certificates are widely recognized internationally.
2. Domestic certificate: issued by authoritative diamond appraisal institutions in China, such as National Jewelry and Jade Quality Supervision and Inspection Center (NGTC) and Jewelry Testing Center of China Geo University. These certificates are widely recognized in China.
A certificate usually contains the following:
1. certificate number: each certificate has a unique number, which is used to identify the authenticity of the certificate and query the certificate information.
2. Appraisal result: The certificate will clearly indicate the weight, color, clarity and cutting grade of the main diamond.
3. Diamond size: The size of a diamond, including its diameter and thickness, will be indicated on the certificate.
4. Shape and cut: the certificate will indicate the shape (such as circle, ellipse, heart, etc.). ) and the cutting grade of the diamond.
5. Clarity characteristics: The certificate will describe the clarity characteristics of the diamond in detail, including the type, location and quantity of defects.
6. Color characteristics: The certificate will describe the color grade of the diamond in detail, such as D color and E color.
7. Spectral measurement: The certificate will indicate the spectral measurement results of the diamond, including refractive index and optical density.
8. Fluorescence reaction: The certificate will indicate the fluorescence reaction of the diamond, such as fluorescence and non-fluorescence.
9. Laser lettering: The certificate will indicate the laser lettering of the diamond, generally the certificate number and the weight of the main stone of the diamond.
10. Signature of the appraiser: the certificate will have the signature of the appraiser to prove the authenticity of the diamond appraisal result.
It should be noted that different certificates may contain different contents, depending on the actual certificate.