If you like something more petite, this is a 2 3/8" translucent resin Surfboard with a 3/4" silver-plated anchor charm and sand from Horseneck Beach in Westport MA but you can choose sand from more than 200 more beaches worldwide to customize your necklace.
Necklace is a 17" waxed cotton cord  with a lobster claw clasp and 2" extender.