Martha Cayatino Purple Spiny Oyster Naja PendantNavajo handmade pendant by artist Martha Cayatino. Hand stamped sterling silver with a beautiful purple spiny oyster stone. Spiny oyster shells have been used in jewelry, sculpture, ceremony, and trading in Southwestern and Central America since at least 4000 BCE. Harvest from clusters 165 ft under the ocean along the Pacific coast, these precious materials require skilled divers to harvest. The earliest illustration of spiny oyster diving diving in