The process of certification of gold jewelry can be done through different methods, including:

• Certificate of Authentication: This is a document issued by an organization like the Gemological Institute of America (GIA) that lists the characteristics of a given piece of jewelry, including its origin and any special features. It is also known as a grading report and provides information about the quality and characteristics of the jewelry.

• BIS Hallmark: This is a hallmarking system for gold and silver jewelry sold in India that certifies the purity of the metal. It certifies that the piece of jewelry conforms to a set of standards laid by the Bureau of Indian Standards, the national standards organization of India. The hallmark consists of several components, and the testing of the jewelry as well as the marking is done in authorized hallmarking centers.

• SGL Certification: SGL (Solitaire Gemmological Laboratories) is a gemological laboratory that provides certification services for diamonds and gold jewelry. To verify if your gold and diamond jewelry is genuine, you can take it to any branch of SGL, submit it for certification, and receive the certificate within one day.

• Hallmark Certification: This is an authenticity certificate that declares the purity of the gold in the jewelry. It is done by BIS authorized hallmarking centers and is required for gold jewelry sold in India.

In summary, the process of certification of gold jewelry can involve different methods, including certificates of authentication, hallmarking systems, and certification services provided by gemological laboratories. These certifications ensure that the jewelry is genuine and conforms to certain standards.