Was a highly polished flat base. Some ware which leads me to think its most likely 1950's/1960's - it gives that sort of feel. (don't ask me what i mean though, or how to describe my feelings! I have around 1000 paperweights all sorts of bits and pieces and this feels to be period but clearly post-war).
Either way, I like it and at £4.00 I can't complain - building up a nice collection of lepidoptera!!!