Although two tone gold rings were not uncommon in the late 1930's this is a very unusual ring. It is 18K yellow gold filigree ring with a 18K white gold bezel and prong set Diamond solitaire. I typically only see white gold filigree rings.
This is a Jabel ring, the noted manufacturer with a long history in New Jersey jewelry making. The ring is size 5.75 and weighs 3.8 grams. It can be sized by your local jeweler and is in excellent condition with only minor scratches on the inside of the mount.
But the star of the show is the 1.03 CT Old European cut Diamond. It has impressive clarity VS1 at the worst. The color of the stone is @'J' which is common for stones of this era and cut. The great thing is that the yellow gold of the mount has a compensatory effect and the Diamond faces up remarkably white.
If you are looking for a truly unique wonderful 1 CT Diamond solitaire this is the one.