nice glass - intriguing how such a piece should avoid picking up any wear. From what I can see in the picture, plus your words about the piece, my thoughts are c. 1850 or perhaps even later. You don't tell us the height, but I think we're looking at a bucket bowl which has a heavy appearance, and just makes me think more mid to late Victorian.
But who knows - like so many drinking glass related pieces, precision seems difficult to achieve.