Hey Chuck G......yeah, "single seam" is probably not a good description of this mib. I think it looks a lot like other Pelt slags I have had, where two ends are folded over together but not to the extent where the seams merge. The fold line where the ends meet can look like a seam or cut line. I think that is what is going on with this marble. The fold line where the ends meet looks like a seam, but I think the cut lines are actually where the yellow opaque glass ribbons (for lack of a better word) abruptly end on either side of the fold line. Probably violating marble description convention here but this is what I'm seeing.