14k Gold Solitaire Diamond Engagement Ring Stamped MAICO 585 Resized, so bottom is a bit thin. I wouldn't recommend making it larger, but should be ok to make smaller inside diamater of 18mm-18.36 so it's close to a size 8 Diamond about 4.25-4.4mm diameter and 2.75mm height using my micrometer See Photos Received in 1996, was his Mothers, I only wore it a few months and it's been stored away ever sence. (never found him to return it and he never asked for it) Time to move it along, Let this be YOUR Special memories maker!