Vintage Turquoise Dots Dome Ring in Sterling Silver Ring Size 6

Vintage 1930s sterling silver dome ring that is set with 16 reconstituted turquoise stones. This sort of turquoise can get chalky with age and with a jeweler's loupe I can see that the tops of these stones were oiled or coated with a protective coating of some sort.  One stone appears to have been replaced at some point in time. It is a size 6 and the dome has a diameter of 3/4". No hallmarks. Acid tested. Weight: 5 grams. A very rare and desirable design.