Featured What kind of leaded lamp shade? Grandma thought Handel--doubtful!

ah, I see. My apologies, I skimmed the thread and then misread what you were saying.

 

that is great news montanap Hope you are able to find a nice base for it!

You hear often enough on the antiques roadshow 'A mark is the last thing you look for'
I imagine that a company that deals in Handle (and other) lamps would know simply by looking at the design and construction what it is or isn't.
Komokwa, it is like you being able to tell an authentic First Nations carving from one done in Bali (or elsewhere) without looking for a signature

 

Looks a bit "off" for Handel. Found this Unique lamp on Pinterest. As usual with Pinterest, the link is a dead end so no more information. Shape and execution is more similar to yours.

 

I think one of the design issues is that both Handel mosaics and the Unique that @verybrad posted have 8/9 full rings of the non-floral glass squares and the OP's has 6/7 rings. Makes for a slightly clunkier look.