I used 5/8″ bolts from the hardware store and antique silver rings with three strands of 2mm black leather cord braided together. Closure is with wraps of silver plated copper wire and a silver swivel lobster clasp–length is 7 1/2″
I found this sand dollar on Pacific Beach in San Diego while on a trip with my grand kids–brought it home and used it as a pendant. The pendant could also be worn on leather, ribbon, or cord.
The sales clerk at Ace Hardware wondered about the reason I was buying washers and bolts–she said that she wouldn’t have guessed that I was making jewelry using them.