Purchased this at a estate it has the letter c with a circle around it (in guessing the date mark) and then it has a s w with a crown under the w and a box around it then 92 the ring appears to have been resized so I am guessing the platinum mark was cut out I acid tested it and tested positive for platinum it is a size 10 and weighs 4.3g and has 3 high quality deep blue turquoise settings