How do I make realistic looking glass?

Wow, such a stupid mistake, probably happened when I tried creating the material a second time. Now the clamp node is going into opacity, I’ve rebuilt the scene and the lightning and still nothing has changed :confused:

Constant 0.35 into Opacity:
604719905a8c32c331dce60314110e846d2a8477.jpeg

Clamp into Opacity:
2a4a8d05b41a0ddf1f4c2f5bebac4c909122d9c6.jpeg