Vintage Gold Filled Necklace with Citrine Color shops Stone or Crystal

Stunning vintage 50s gold filled pendant necklace. Has round faceted citrine color stone or crystal with open back, set in leaf shaped setting. Pendant (not including bale) measures 3/4" height, 1/2" width. Chain measures 16" with hinged clasp. It is marked Gold Filled and has a makers mark which I cannot decipher. Has some tarnish and surface wear, no chips on the stone. shops