Take that back! Out of all the antique whistle buttons Online only a few have the raised center (nipple) that is so essential to this design. I have art nouveau buttons with this type of raised center and a few ancient shell, , fossil and operculum buttons and beads that come close, but after studying these wonderful beads again I realize it would not be possible to substitute anything for them in a jewelry design compromised entirely of ancient beads... the patina and hand carved stone is so unique... simply unmatchable.