Sterling Silver Ring with Australian Opal Size 6.5

Vintage 1970s lost wax cast sterling silver ring in size 6.5. It is set with a genuine Australian opal. It is a natural stone that was backed for strength. It has bright play of color with hot pink and blues, greens and more. Face of the ring measures  3/4" long. Weight: 6.6 grams. No hallmarks. Acid tested.