eBay

Vintage Cast Iron & Metal Ceiling Mount LIGHT FIXTURE w/ old Bubble Acorn SHADE:

extends about 10" from ceiling (photo 10)
glass w/ dimpled bubbles Acorn shade included (photo 5)

opening has an approximate 3.25" diameter
4 screws hold shade in place

heavy black ornate cast iron light fixture (photo 4)

paint has come off in many places

lightweight black metal bowl connects at ceiling

no connector other than the metal bowl
tarnish inside the bowl
Underwriters' Laboratories label inside bowl
"Issue No. C. 263, 831 - Action Lighting of Indiana Inc., Elkhart, Indiana" inside back

this light fixture will need rewiring with a new socket, etc.
please email with questions

more detail:

A hollow metal pole, which is rusty, holds the wire(s). The pole is threaded and a nut/washer holds the fixture to the mount (photo 9).

No cracks in the metal that I see or feel. The seams, however, may appear to be cracks.

No dent in the metal mount, but the very top (nearest the ceiling) is not perfectly round--it's slightly off (photo 12).