Beautiful Australian Opal a friend mined in Australia in the 60's & 70's beautiful flash in this stone set in a sterling silver made in USA setting. October Birthstone or 13 Wedding Anniversary Stone Necklace/Pendant/Slide/Enhancer. Our friend loved to visit and spend time in the Andamooka & Lightning Ridge Mines. size of this pendant is 1 x 9/16 inch or 16 x 14mm