Hi Mary Anne,
i believe the term for this deep cutting is Intaglio,
if you use the search facility on here, you will find a lot of references to the term. (try google as well)
Moser did this type of cutting, but a number of American companies were very good.
Its a super lamp, i would think more likely American. Hopefully you may get some more suggestions
from others. I expect date is 20s 30s 40s ?
( I know theres some Moser experts on the board, also US Crystal fans)
Good luck,
Andy