Generally, the diamond ring certificate will have a column labeled "Carat (CT)" or English "Carat Weight", which is the number of carat diamonds, according to the international standard 1 carat =200 mg =0.2 grams.
There are about three kinds of diamond ring certificates on the market: GIA certificate, NGTC certificate, IGI certificate. From the data of these certificates, you can see how good the quality of the diamond ring is.
NGTC certificate, the full name of the National Inspection and Appraisal Center, is a national-level professional quality inspection institution for jewelry and jade authorized by the relevant competent authorities in accordance with the law, and is also an authoritative institution for the detection of jewelry and jade in China, mainly for the identification of finished diamond rings.
The IGI Certificate is the oldest gemological institute in Belgium and the largest jewellery appraisal institution in the world.
It is worth noting that these certificates have anti-counterfeiting codes, you can go to the corresponding official website to check the authenticity of the certificate.