Sadly, not a Tiffany Table Lamp...So What is this Gorgeous Beaded, Floral Gem then?

1st, I am unable to load the first picture any other way apparently, sorry its "on it's side."

So. For decades, my grandfather (back in South Boston, MA) told my parents that this gorgeous family-owned Tiffany-Style (or so I assume) table lamp was a True Tiffany Lamp! However, after speaking to & sharing pics with the Go-To Tiffany expert, it appears that he was fibbing...I'll never get to know if he knew he was fibbing or if he was just passing on the knowledge that he had been given as a child growing up around it. The expert had told me that he had never seen anything like it but he was certain that it was not a Tiffany. The 1 part he seemed stuck on was the bottom base (where there would be a signature), or lack of a base, to the lamp. He said that Tiffany would never have made a base plate like that. I agree. It looks to me as if part of the base is now missing. It looks unfinished and I can't imagine anyone putting all of the effort that they did in creating this lovely lamp would have suddenly stopped and just threw together such an unfinished looking base plate.
I have a few hypothesis to why the base plate is missing...if it is, but perhaps someone can hopefully recognize this style/maker and/or if this base is complete or if it was "vandalized" - I would love to learn more about this Family Gem ;-)

18.50" X 16.50" inches approx.
It is still fully functional.
Thanks to 1 kind gent on this site, I now know the base is green onyx.

Engraved on both of the sockets is
"250 W BRYANT 250V
PAT'D NOV 26, 1907
MADE IN U.S.A"
And engraved by both of the lamp pull chains is "PRESS"