What does it mean when Jewellery is stamped 428?

A stamp of 428 on jewelry indicates that it is made of 42.8% pure gold, which corresponds to 10-karat gold. In the context of gold purity, the number reflects the gold content in relation to other metals. The remaining percentage typically comprises alloys that enhance the metal's durability and color. Thus, 10K gold is a popular choice for its balance of affordability and strength.