How to Identify Blenko Glass
what is a pontil mark
Antique Bottles: Identification & Valuation Guide
Question: What Is Pontil Mark On Glass?
Bill Lindsey on How To Read a Bottle
Like the other pontil rod types, this one was probably removed by sharply tapping the rod near the attachment point.
The pontil is characterized by a tiny finger of glass that is folded over at the cut-off point and partially melted into the marble surface.
There is no pontil at all.
It is also commonly referred to as a graphite pontil.