What does QG STER stamped inside a ring mean?

The "QG STER" stamp inside a ring typically indicates that the ring is made of sterling silver, with "STER" being short for "sterling." The "QG" may refer to the manufacturer or designer's initials or brand. Sterling silver is an alloy that contains 92.5% silver, with the remaining 7.5% usually made up of other metals, often copper, to enhance durability.