Hand blown art glass bowl - fluted top and with stripes

My latest find is a hand blown purple art glass bowl with white stripe and fluted top. The glass feels very thin and fragile (no chips or damage).
The continuous white stripe is inside the glass (you can feel it a bit on the surface).
There is no identifiable mark or signature.
On the bottom of the bowl there is a ground pontil (1" in diameter).
The bowl is 9.5” across the top, 4.5” across the bottom and 4” high.
If the amount of greasy dirt and filth that was on top of the glass was any indication of age - the item must be very old.