Vintage Sterling and Crystal Aurora Borealis Screwback Earrings Marked STERLING and a Makers Mark

This lovely pair of vintage 50s or 60s screwback earrings are Sterling and have crystal aurora borealis round and pear cut rhinestones with a lovely leaf in sterling. They are about 1 1/8" long and the bottom is a dangle. They are in like new condition with STERLING and a makers mark that I can't make out on the screw head.