Hallmark Stamp k12 on Gold Earring

by Cindy
(Texas, USA)

There are pair of what look like real gold earrings, but only one is hallmarked and the stamp reads k12. Does this mean it's solid 12K gold?

Sorry, but my camera won't take a clear pic of the hallmark. It's too small. So I can only ask if k12 (and no other marrkings can mean 12k. I inherrited these from my Aunt who was in her 80's, but that's all I know about them. Thanks.