Topic: Cavalier marriage goblet? jar help please.

[flying free]

these are closeups ish of a piece I own.  If you enlarge them pressing control and the + button they should enlarge more and still be in focus.
m

[flying free]

As I say, I don't know about the blank, but I did have an 1830s Hyalith Lithyalin piece that was absolutely impeccably cut to the nth degree, all over.  Amazing work. i.e. I don't think the impeccable cutting negates it being an old piece (If I understood you correctly)
m

[flying free]

Two French pieces here if you scroll down, a bottle and a glass.  They are dated 1722 so a good bit earlier than you were suggesting, however it's still interesting to see the enamels close up.
http://www.lesartsdecoratifs.fr/francais/musees/musee-des-arts-decoratifs/collections/dossiers-thematiques/arts-decoratifs-et-design/verre/chronologie-du-verre/
m