4th gen headlight lens material?

Does anyone know what the material the headlight lens are made of? (glass or plastic)
I ask because I want to retrofit some projectors in the housings but would need to get rid of the fluting. As such I tried to source some aftermarket clear lenses but came up empty. So I'm going to try and make some out of some plexiglass but only if the originals are out of plastic. I've read on hidplanet a bit and it would seem the glass ones are prone to cracking when trying to cast a negative of the inside due to the light expansion that occurs when curing material inside.

anyone know for certain?

thanks!

 

It's glass. You're gonna blind the crap out of everyone with the 4th gen lamps. I say go led.

 

I would make clear lenses and put projectors in it. Damnit! Glass makes it problematic :-(

 

It's glass, don't ask me how I know.