Ancient Roman Ring With Green Glass Stone

This is an ancient Roman ring that came from the year 500 or 600. I believe the metal is bronze and the stone is not blue; it is actually an extremely deep green, the same color as an emerald. I think it is a glass stone, but I am not sure about that. While I am not selling this ring, I would love to see whatever information that may be available about it: a more accurate year, how much it may be worth, whatever history that can be found about it.

Fair