Hi Lady P Is that stopper hollow. Sometimes also you can guess on crystal because of the weight. If you put crystal under a germcital light it turns a pretty light blue, but it will still never turn color. Looks to me that item on top of stopper is same color as the string on bottle. The oldtimers were good at a marriage between stoper and the bottle grinding as Harry says it made the two tight. I would like to buy that at a 10% dealer and a 5% Senior discount.