or simply opaque white glass, depending on which side of the pond you happen to be

It looks an old style design with this six way crimp on the ruffled rim, but I bet more than likely it only dates to the last 25 years, somewhere. I always plump for the States with these pieces, as I understand the USA were very big with original and reproductions of this material right through into the mid C20, and beyond - but I stand to be corrected. Difficult to assess base wear on some of these things due to the coarse finish to the edges, thus preventing wear to show clearly - some parts of the rim still carry slight projections, presumably because of poor mould closure, and there are four mould seams showing on the upper side of the foot. Guess you'd call the surface a raised diamond pattern. If pushed, I'd plump for Fenton, somewhere in the 1960 period, or close by (I did look through Belknap, my only book on milk glass - but no luck) - height is something like 6.75" - about 170mm. Any chances I might be getting warm, and thanks for looking