If this is gold, the purity is 7.8k (7.8/24 = 32.5% pure gold by weight). This is not a common alloy, and may be foreign. SL is probably the manufacturer's mark or brand. Are there any other marks?
Hey thanks guys. It definitely says 325 and not 925. There's some black stuff/dirt in the upper part of the 3 that makes it look like a 9. An older guy I talked to also said it might be foreign. The only other marking on it is a M with a circle around it, which I'm guessing it means for men.