Do you have a ring that fits you, but flips side to side? One way to adjust a large stone ring from flipping side to side on your finger is to flatten the back of the shank, which is the part of your ring that faces the inside of your hand. This won’t work if you have large knuckles. To accommodate a large knuckle, the jeweller will either need to solder gold balls inside the shank or, if you have extra large knuckles, the shank needs to be changed to a locking shank that opens and closes on a hinge. However, if you don’t have large knuckles, then flattening the shank should do the trick.
