Margi - the proportions don't sound very early C20 - perhaps more of a modern design. On reflection don't think you have a ground pontil - the light is picking up what look more like fine striations (lines) in the surface of the glass - which appear to run all one way. However, does'nt seem to be getting us anywhere with an attribution. If you have a piece of genuine old 'cranberry', try comparing the colour with this one. Sorry this isn't much help. If I may ask, what was the source of this item? Paul S.