For your consideration is a very old looking ring. I am unsure of the age.
It appears to be mahogany obsidian. The colors look to be black & an orangey red color.
I have acid tested this ring and both the band and the setting test positive for sterling silver.
I do not see any marks inside the ring, but that could be due to the darkening/tarnish.
Size 5.75.
I have not attempted to clean this ring; I have left it in its original condition. It shows signs of age and tarnish. There is a small place at the top of the ring between the setting & the obsidian that is a teeny bit loose, but I did not notice this until pressing down on the obsidian.
The pics may make the ring look slightly brighter & larger... I have cropped the pics in an attempt to show more detail.
Please be sure to view all photos before purchasing.