I’m a glass artist who makes handmade glass beads- even made a few to wear “Pandora” style. If you post a picture of the bead in question, I can give you my opinion. I do know that the authentic Pandora glass beads have “Pandora” stamped on the silver outer core of the bead. Does yours have this stamp?
https://forum.purseblog.com/threads/is-my-pandora-murano-glass-bead-a-fake.617291/