Ring is a size 7.75. Weight is 11.5 grams so it is solid. Face of ring measures 3/4” top to bottom. Ring tests as sterling. There are no markings. I am not sure if opal is a doublet as it is bezel set and without being able to see back of stone I personally am unable to tell. Colors are deep blue with red. I have polished lightly. There is a blackened tunnel around stone. Please see photos and ask questions before bidding. Thanks for your consideration.