Pretty piece but it is not opalescent glass, it is opaline glass

and I agree with Christine, almost certainly Bohemian.
I doubt you will find a maker for it... but it is always worth keep looking. It is possible that it
might have had a lid maybe.
I might put it at late 19th century but only because the decoration reminds me of a similar enamel I have dating to around 1880 I think. That's no guarantee though because enamel dec styles will of course run over many periods.
m