I don''t have an expensive gemstone tester to show you but I recently got a diamond tester and I am showing that it has hardness to it. If it is glass, the tester doesn''t light up. It lights up to the correct hardness for Tourmaline.
This is the perfect size for a ring and the cut would fit just about any setting. I am so tempted to keep it myself but I don''t wear the rings I already have lol