This is an exciting art deco-styled neckpiece. Despite much research and consultation with experts, I have not been able to determine its provenance.  No markings on the back indicate the metal or the grade thereof.  There is definitely some silver as it was tarnished when I first possessed it.  Polishing revealed a coppery hue coming to the forefront.  The stone is a peach color, and the setting is so unusual - several "pegs" of metal have been created around the stone.  The fastening is a "hook and eye" type latch.  It is almost a choker length - sits right on the bottom of the neck.