hello m - I had just typed the following......am I also doing something wrong in commenting....?? please delete pronto if I am out of order.
I'm a great believer in the maxim that you shouldn't open your mouth if you don't know your subject, and I since I know less than nothing about Daum......here goes. These images seem not to show any deep cutting/etching, so would suggest that this is not cameo decoration in the usual sense, although it was, apparently, etched Art Nouveau cameo glass that introduced Daum to the world of decorative glass. This particular type of image is untypical of 'Art Deco' style - which doesn't mean it wasn't made 1920 - 35, but that stylistically it owes vastly more to pre first war fashion (Art Nouveau) than the geometric imagery that came later. Some forms of decoration, from this period, have been produced by flashing, or other forms of colour staining, and used in conjunction with acid etching it is possible to alter, selectively, some of the underlying colours, and the rim chip and the clear base might possibly indicate that this piece was decorated in a similar way. The assertive use of the name Daum might be considered misleading as, of course, this type of decoration was also created by other factories, and I'm not quite sure why it......"must date to around 1920".
Nonetheless it is an attractive piece of glass, and I guess back lit would look very beautiful.