Vintage Sterling Silver Mexico Modernist Onyx Cabochon Ring Size 6

this is a vintage Mexican sterling silver ring with onyx cabochon. It is signed but it's hard to read the makers mark EDM? It currently fits a size 6 finger but it's open design allows it to be adjustable. Stone measures 1/2" x 3/8". Front measures 1" long in total. Weighs 5.8 grams.