What does the z in a circle mean in A 10ksr ring mean?

In a 10ksr ring, the "z" typically indicates that the ring is made of 10-karat gold with a specific zinc alloy. The "sr" stands for "sterling," suggesting that the ring may also contain silver or is part of a design that incorporates sterling silver. Overall, the "z" signifies the alloy composition that contributes to the ring's durability and appearance.