Bone? pendant on copper-alloy slip-knot ring

Bronze ring with bone hanger. Bronze wire ring, with sliding knot, - tapered terminals coiled tightly at either side but set apart. Suspended from it a clip made of a folded strip of sheet bronze with a bronze rivet though its lower end holding a piece of flat bone decorated on both sides with double-ring-and-dot ornament, upper surfaces (very small piece survives) apparently originally curved.Part of a comb? Or has it been a decorated disc?Remains of 5 ring-and-dots on one side, irregularly placed.