I'd also put this one away for a while - until by chance I looked at plate 27 (page 103) in Jackson's Whitefriars Glass. The similarity of shape seems obvious, so possibly a finger bowl, although mine is not the same amber colour, and without suspended particles of copper. On mine there is really quite fine machine threading applied to the underside of the wavy flange (an eight way crimp) - and the thread itself is of a very delicate coppery pink. The body is clear, and the flat base part has slight optical ribbing. A quite large ground and polished pontil mark. 16 cms. wide and about. Needless to say, I don't have the bowl, if that indeed is what it is part of. Wear on the base makes me think it is possibly quite old - the early part of the C20 perhaps. Grateful for any information please. Paul S.