K18 chain earrings featuring a black cross charm. - Design: Black cross charm - Material: K18 chain - Stamped The cross part is onyx, and the chain part is K18, which is what I purchased it as, but there is no certificate of authenticity or accessories. There is a stamp on the post, but I couldn't capture the marking clearly in a photo. I really liked this unique design and rarely saw this type. I'm listing it because I haven't worn it recently, but I loved it, so I might suddenly remove the listing. I've categorized it as women's, but since it's onyx, I think it would look great on men as well. This is a used item and has been stored at home. Please refrain from purchasing if you are concerned about this or are very particular about condition. I apologize if there are any overlooked scratches or stains. Thank you for looking.