Antique Frosted Matte Green Glass Pendant Shade Extra Large Library Schoolhouse

Description

Vintage antique industrial or commercial green matte frosted glass pendant light shade, probably commercial or industrial in origin, perhaps  library or schoolhouse light shade.
Thick heavy frosted matte green glass; 1/4" thick and approximately 18" diameter and 12" high.
It weighs over 12 lbs. unboxed.
It could be called a bell shape with a bottom tip or modified bell shape ?  or it looks to me like an inverted Hershey's Kiss.
This is a vintage or antique glass shade, most likely from a business or a large building like a library or schoolhouse. We do not have more information about it.
It is a matte finish and shows age / wear; it does not have any gloss or sheen, and has some whitening of the surface - not sure how to restore whatever the original surface might have been. Finish seems to show the effects of outdoor use and age.
The glass is not chipped or cracked.
There are three holes in the mounting part; mount is about 4 1/8" inside diameter and 4 3/4" outer diameter (see photos 7 and 8).
This listing is for the glass shade, we do not have a fixture.
Please see photos and feel free to contact me if you have questions.
I pack carefully and usually ship on the next day after payment is received.
Thank you for looking and for your bid!