Boulder Opal hand crafted vintage sterling silver gemstone necklace

Boulder Opal hand crafted vintage sterling silver gemstone necklace. Good used condition with little signs of normal wear. Unique prong set Boulder Opal cab in sterling silver. You can see the hand worked tool marks on the back of this piece. Appears to have what looks like an etched unidentified signature on the back. Comes with sterling silver chain. Acid tests positive for sterling silver. Necklace measures 18 inches long. Pendant measures 1 inch tall and 1/2 of an inch wide.