Not sure. Tough to tell without better pictures or having the piece in hand. I would suspect that the sides could be manipulated inward in a similar fashion as those pattern molded pieces that were expanded.
I'm hoping that others may recognize the piece and have some input... I am curious about it.
looks like the base to a non bottle vessel of some type, or possible a barber type bottle. Doubt it was a cone ink... Would have been a substantial dig either way though! Sweet piece of glass...
OK, some of these pics aren't the best, but they were the only way I could get the pattern to show up well. Others turned out rather good for my crappy camera.
What makes you think non-bottle? It's almost exact to the size of your average run of the mill cone ink. :Note to self, get pic of bottle next to cone ink.
I searched for even a piece of the top, imagine that I didn't find the pieces to a broken bottle in a hillside dump.[]
This one was a cloud going over, but the ribs stand out more.