thank you so very much for your very interesting post, Will! Yes, my bead is made around what is called sand core, and my husband did know that type of alabastrons - I said earlier that his collecting interest is antique glass glasses, jars etc. He remembered the sandcore technique, which was one reason for us to think the bead would be authentic, we just thought that beads were made that way too. I already said, never again invest money in something of which you know only half of the story :)

Anyway, you are most probably right with the residue on the bead. We removed a small amount from the outside of the bead, was very easy, and it looks very similar to the one on your jar, only not as bright, just more dirty.

I am so grateful for all your help. Even if the result is a bit depressing, I must no longer be puzzled over the bead's authenticity. And I learned a lot!