This is a really unusual specimen of Durand glass. This dates from the later days (by shape number) and is an unknown decor. It is a white pattern in a clear glass. I've been looking for another like it or a pattern name for quite a while now but still haven't found either.
This is a very large piece in a kind of bell form. If I recall correctly it's about 9 inches tall or maybe 10. It is a wide piece too. This is just right for Roses.