Unisex Sterling Silver torquoise ring size 8.75

This vintage classic piece has a beautiful defined mark that my research hasn't let me identify it yet. So if anyone knows please let me know. It has some wear normal to its age but is still very beautiful. It is a tad less than size 9 as shown on the pic so i am putting it at 8.75. Kindly refer to the photos for the wear and condition of the item. A new box will be provided for storage or if you wish to give it as a present for any special celebration. Questions and offers are very welcome😊