Certificates and stamps play a crucial role when purchasing jewelry. They serve as proof of the authenticity and quality of the jewelry. For gold and silver, fineness stamps such as 585 (14 carat) or 925 (silver) are reliable indications of the material content. For diamonds and gemstones of 0.5 carats or more, a certificate from a renowned testing center is essential as it contains information about the quality and characteristics of the stone. These documents give you confidence in the authenticity and value of the jewelry.