GIA - American Gemological Institute
Gemological Institute of America
In 1931, GIA professional non-profit organization was established in Los Angeles. With the purpose of educating and serving the global gem industry, and with the goal of improving the moral concept of the industry and ensuring the full awareness of the public, it enjoys the reputation of "World University of Gem and Jewelry Industry".
|GIA's credibility The GIA certificate issued by the GIA appraisal room is considered to be the most credible certificate in the world. GIA diamond grading report and GIA diamond processing appraisal report are considered as the world's first gem certificates. GIA is the most popular certification authority in the United States.
|GIA's Contribution GIA is the founder of the well-known diamond 4C; GIA is the common birthplace of the international diamond grading system; GIA is the most trusted diamond grader in the world; GIA invented the first binocular microscope for gemstones combined with dark field lighting; GIA is the origin of the G.G. course for gemologists; The education diploma of GIA is accepted by the world; GIA has the largest gemological library in the world.
GIA's authentication center GIA authentication center headquarters | US West Coast authentication center Thai authentication center | Hong Kong authentication center Indian authentication center | Botswana authentication center
AGS - American Gem Society
American Gem Society
AGS is the abbreviation of the American Gemology Society, and is the world's most authoritative top appraisal institution focusing on diamond cutting. AGS was founded in 1934. Its founder is Robert M. Shipley. He is also the founder of GIA, the American Gemology Institute. Like GIA, AGS is the most famous diamond rating organization.
AGS is committed to developing the diamond grading system. The biggest difference between AGS and other appraisal systems is that in addition to the weight, AGS grades the cut color clarity of diamonds into 11 grades from the best 0 to the worst 10. In addition, the AGS diamond grading system formulates the most important cut in the 4C of diamonds, thus bringing diamond cutting to a new distance.
Is the AGS certificate authoritative? The AGS certificate is an internationally authoritative diamond grade certificate. In particular, it attaches importance to the grading of diamond cutting, formulates diamond cutting, and then brings diamond turning workers to a new distance. AGS lathe worker rating is based on the 0-10 bit rating standard. Like GIA, AGS lathe worker rating is the most famous diamond rating organization. Its authority is self-evident. Diamond cutting is an important factor affecting diamond prices. Those who attach importance to diamond cutting may choose AGS certificate.
IGI International Gemological Institute
IGI was founded in Antwerp in 1975, and now it has become one of the largest international gem colleges in the world.
The patent of IGI Laser Scribe System Mark pioneered the method of permanently marking diamonds with laser; IGI is the first laboratory in the world to issue the identification certificate of finished jewelry products; IGI is the first laboratory that can issue dual brand certificates for famous brands in the industry; IGI has created the "Eight Hearts and Eight Arrows" diamond certificate which is respected by the world; IGI is a well-known professional appraisal institution in Europe and the United States; IGI has issued up to 500000 type identification reports every year.
Distribution of laboratories: Antwerp, New York, Hong Kong, Mumbai, Bangkok, Tokyo, Dubai, Tel Aviv, Calcutta, New Delhi, Trinidad, Surat, Chennai
HRD - Belgian Diamond High Council
Diamond High Council
HRD, the full name of which is Diamond High Coun cil HRD, and the Chinese name of which is "Belgian High Class Diamond Parliament", was founded in 1973 and is located in Antwerp, Belgium, the world diamond center. The royal certificate used to present diamonds to the king of Belgium is the most respected certificate in the European market and one of the most authoritative diamond inspection, research and certificate issuing institutions in the world.
The principal shareholder of HRDAntwerp is Antwerp World Diamond Center (AWDC for short); HRD is the official contact between the Belgian diamond industry and the government, and promotes the diamond industry at home and abroad; HRD hopes to further develop Antwerp as a world diamond center; HRD represents Belgium, foreign governments and professional organizations in the field; HRD coordinates various things and provides various services in the name of the diamond industry; HRD hopes to promote relevant knowledge in the diamond field by promoting jewelry and jade market transactions.
The International Diamond Council (IDC) negotiates the HRD international diamond grading standards for HRD, and the HRD diamond appraisal center conducts the appraisal in accordance with IDC rules. HRD plays an important role in identifying the imitations of diamonds and the reasons for the color of colored diamonds. HRD diamond appraisal report mainly provides efficient and fast services for diamonds below 1 carat.
For diamond identification, HRD abandons manual detection, and all identifications are carried out strictly with advanced instruments, so as to avoid the influence of human factors and give the most authoritative certificate authentication on the principle of fairness and justice. After rigorous evaluation by HRD precision instrument, a detailed report can be made on the color, clarity, weight and cutting ratio of diamonds.
National Gemstone Testing Centre
The national inspection certificate of Ngtc, the full name of which is the National Jewelry and Jade Quality Supervision and Inspection Center, is a national certificate of China. For the ngtc certificate, it is not only for the inspection of bare diamonds, but also for the inspection of finished jewelry inlaid with diamonds. NGTC is also the only partner of GIA in Chinese Mainland.
NGTC has issued four identification certificates for diamonds and diamond inlaid products in total: the "Classification Identification Certificate for Inlaid Diamonds" and the "Identification Certificate for Jewelry and Jade" are issued for diamond inlaid products. The "Diamond Grading Certificate" and "Diamond Grading Report" are certificates issued for bare diamonds.
Identification Certificate of Inlaid Jewelry and Jade
The "Jewelry and Jade Identification Certificate" mainly refers to diamond inlaid jewelry whose diamond size is less than 20 points (0.2 carat). There is no specific grading conclusion for color and clarity on such certificates. Consumers need to pay attention to the inspection conclusion. If it is natural diamond, it will be marked as "diamond" in the inspection conclusion. If it is synthetic or processed diamond, it will be marked as "synthetic" or "processed" in the inspection conclusion.
Inlaid - Diamond Inlaid Classification Certificate
The "diamond inlaid grading identification certificate" is a common certificate for inlaid diamond products, mainly including:
Certificate No.: the identification certificate number of the jewelry, so that consumers can check the authenticity of the certificate online
Test conclusion: describe the type of diamond jewelry. If it is a natural diamond, it will be marked as "diamond" in the inspection conclusion; if it is a synthetic or processed diamond, it will be marked as "synthetic" or "processed" in the inspection conclusion.
Total mass: describes the total weight of diamond jewelry. Since diamonds in diamond inlaid products have been embedded in metal, it is impossible to accurately measure the weight of diamonds. The certificate will indicate the total weight of jewelry
Shape: Describes the shape of a diamond.
Color: describe the color grade of diamonds according to national standards.
Clarity: describe the clarity grade of diamonds according to national standards.
Table width ratio: describes the ratio of table top to diameter in diamond cutting.
Pavilion depth ratio: describes the ratio of pavilion depth to diameter in diamond cutting.
Precious metal detection: describe the metal materials used for diamond jewelry.
Remarks: The description of other characteristics of diamonds not mentioned in the report, and the specific treatment method of treated gemstones.
Bare Stone - Diamond Classification Certificate
The "Diamond Grading Certificate" is a certificate issued for bare diamonds. For bare diamonds above 1 carat, the National Gem and Jade Quality Supervision and Inspection Center must issue a detailed "Diamond Grading Certificate" according to national standards. Compared with the "diamond inlaid grading appraisal certificate", the "diamond grading certificate" not only includes all the contents of the "diamond inlaid grading appraisal certificate", but also gives a more detailed description of the "cutting grade", "decoration grade", "symmetry" and other aspects of diamonds. The "Diamond Grading Certificate" will also provide sketch illustrations of the attributes, location, size, etc. of the inner inclusions of diamonds, so that consumers can have a more specific and intuitive understanding of the bare diamond.
Bare Stone - Diamond Grading Report
Bare stones - diamond grading report "diamond grading report" is also a report issued for diamond bare stones. Generally, for diamond bare stones with small carats, the National Gem and Jade Quality Supervision and Inspection Center will issue a "diamond grading report" according to the requirements of the applicant. The most obvious difference from the "Diamond Grading Certificate" is that the "Diamond Grading Report" does not have a sketch of the clarity of the bare diamond. In the inspection conclusion, the "Diamond Grading Report" also contains detailed descriptions of the inspection conclusion, diamond shape, "carat weight", "color grade", "cleanliness grade", and "cutting grade". However, more professional data such as "Taiwan width ratio" and "Pavilion depth ratio" of diamonds are not reflected.
