It's probably the effetre color like Floorkasp said.
Opaque otherwise is vintage as far as I know, I have some and only saw it for sale once ever.
eta, it is an effetre number, so no uranim or glow. If you want it to glow remember the coe is usually a weird one so use it carefully. I think member Magpie has some czech uranium.
https://squareup.com/store/magpiesglasscache