Can you tell if it's glass or plastic? (tap it on your front teeth)

All I have are the photos. I will ask him if he can tell.

It is glass. Found in Oklahoma.
I've not seen one like it myself.

OK, so we've determined it's glass...

While photographing these Czech glass beads today I was reminded of your bead. These are 8mm beads with a hole that will accommodate a 1mm leather cord (that is, a larger hole than most Czech pressed glass beads).

These aren't old beads; their nice satiny look is due to the type of glass and a semi-matte polish.

Note the mold line around the equator, which is what made me think of your bead.

Sorry, been a busy week!
Those look like a possibilty....I'm thinking it's not very old, I will let him know...probably Czech glass but probably not historical, best guess.
Thank you so much for your help!