HI All , Having just read through this thread I thought I would add my tuppence worth , I think I have to agree with previous comments that suggest modern, more than likely recycled glass, I have seen similar made in Gibraltar and I would also agree with a possible Mexican origin too ,all glass with this type of bubbly metal that i have seen in the past has had a modern origin and I have never come across anything like them that could be given a pre 20thc date,
Not great news but I hope it helps,
Cheers ,
Peter.