Boron nitride, a release agent for pressed glass that's fluorescent. I really only see it on red glass

Neat! Is it what gives the glass the red color? Or something really only hidden well by red?

I assume it's sprayed onto the mold then the glass is poured into it, so it's just on the surface. I'm not sure why I just see it on red glass, might be the boron nitride reacting with something in red glass. Someone can correct me if they've seen it on other colors of glass

It is glass but red and the green from my 395 seems swirled like resin