This is an Art Deco dress clip of outstanding beauty and quality that comes from the 1930s and is most likely imported from Europe, possibly Germany.  A light green carved oval glass stone is prong set in the center of a beautiful shield shaped setting with a variety of handsomely curved silver elements.  The marcasites are all bead set on a superb silver background.  The back of the dress clip is marked with the word "Sterling" and a symbol that looks like a tiny crown.  This is a top quality piece of jewelry history that you will love wearing.  It can be clipped to a suit lapel or a sweater or dress neckline, or it can be hung by a chain and worn as a necklace.  The overall size is 1 1/2" long by 1" wide and it is in excellent condition.  SORRY, BUT THIS ITEM HAS ALREADY BEEN SOLD!

The back of the dress clip:

A close up view of the mark.  Can you identify the symbol and it's origin.  If so, please let me know!: