Silver metal sugar bowl with blue glass insert

I believe it is a fake silver sugar bowl. The overall condition is very good but it is a fake! The blue glass is intact. One hallmark imitates the Austro- Hungarian Diana mark from end of XIX/beginning of XX thus the dating. There is patina outside but I think it is not genuine. The metal weight is 531 g and the glass weights 260 g. The dimensions are: 16x11.5x20.5 cm.  I sell it as a curiosity.