Top grade Spiney Oyster Shell necklace, hand strung in Tucson, Az. It has sterling silver beads at the ends with a sterling silver hook and latch clasp. The Spiny Oyster gemstone is a colorful shell that comes from the oyster species “Spondylus varius”, as the name implies, Spiny Oysters are covered with menacing spines. Spiny Oyster shells are unique, beautiful, and also difficult-to-harvest.