You have a beautiful vase! One of my favorite color combinations is cranberry with yellow uranium opalescent! Unfortunately, a maker might never be definitively identified. Every glass shop was capable of making this. The opal ring where the foot attaches is just a byproduct of the piece slightly cooling just before a hot piece was added.
This could have been done by Richardson, Webb, or Walsh. If you decide to part with it (via eBay), please let me know so I can throw out a bid or two.
and to BFG: I have since taken a newer photo of my double marmalade. It was nice enough to go on the back cover of THE ENCYCLOPEDIA OF OPALESCENT GLASS (7th Edition) by Mike Carwile. Here is the raw photo:http://www.vaselineglass.org/lemonpair5.jpg
If you do a book search for the 7th edition, a big Davidson epergne made from pressed glass made the front cover. (but....that's ok, because that is also my glass and photo!)