Size 7.5, resizable, no hallmarks, c. 1850, 15k rose gold (tests) with very old petite rose cut diamond measuring about .12-.15 points. Has been worn for years, probably with a wedding or other ring next to it - you can see the flattening/rubbing from the two touching constantly. One of the prongs is nearly worn through in one place, but that doesn't seem to be causing a structural problem. Wearable everyday, absolutely adorable and has had a long life, but lots more left.