Antique 18k white gold filigree amethyst ring, circa 1920

Vintage 18k white gold filigree ring with a 11.21ct amethyst.  The ring measures 3/4" long and is a size 5 1/2.  The scrolling filigree work shows through the amethyst at certain angles and the minimal prongs really show cases the stone.  Circa 1920.