Diamond waist. Chow Tai Fook is the largest jewelry company listed in Hong Kong, specializing in Chow Tai Fook brand jewelry, jade and gold ornaments. It is a comprehensive enterprise integrating raw material procurement, production design and retail services. The waist code of Chow Tai Fook diamond ring is at the waist of the diamond, and the waist code of the diamond is also GIA laser code, which is engraved on the waist of the diamond to help customers identify the diamond.