Hello

Please can anyone help with this piece of glass? I found it at the car boot this morning. It is quality glass from around early 1960's but I do not know who it is made by or glass works.
The item is 11 cms wide and 10 cms tall in a deep purple colour with a white band around it and what looks like a deep purple trail over the top fragmenting the white. All of which is melted smoothly into the body.
The base has a snapped off pontil mark and very distinct ground outer ring.
If anyone can help I would be most grateful.
Thank you.
Jazzy64