Abstract: A chain clasp having a base member on which a lock member is pivotally mounted, an opening being formed in the base member with which a space communicates that provides exterior access to said opening and thereby provides for mounting of a free end of the chain on said base member, the lock member being pivotally movable relative to the base member into overlying relation therewith for sealing communication between the space and opening and thereby locking the free end of the chain on the base member.