Beautiful clear diamond in a lovely simple setting. The diamond measures 4mm and appears to be about 2mm deep. I took it to my jeweller for a clean and he estimated it was about .28 of a carat and said it was very clear. Sizing charts show 4mm to be .25 but I don't know if the depth makes a difference. It is stamped 750 for 18 ct yellow gold And also has what looks like O which could be for the size? It fits to my knuckle on my wedding finger which is a size Q these days. Would make a stunning well-priced engagement ring, or just a lovely dress ring. It's really hard to get a photo that does the ring justice. I'll try to borrow a macro lens and get a better one uploaded ASAP.