probably one of those ceramic power insulators
What is this thing?
Let us help you identify that mysterious object you’ve found.
Currently in CHALLENGE mode: If you've got something obscure knocking about, post a picture, and let's see how we do. Please prefix such posts with "CHALLENGE:" so we know we've got a fighting chance.
I'm starting to think it is part of an insulator. It's just so big to be one. It's almost double the size of the the vintage 1950s one above. Maybe one section of a huge high voltage assembly?
Looks like it to me, albeit a bit large ...
It's absolutely huge if it's an insulator.
Looks kind of like a lid for a fermentation crock?
crock-Pot or a bowl probably
The surface is too rough for use with food. It's like small gravel or big sand at the surface.
History of gold mining in the area? Might be a pan for panning gold. Lots of nooks and crannies to trap gold particles. Rough centre surface for breaking up chunks with a finger. It's not a design I've seen before though.
It “could” be a sewer/pipe cap but your geographic location and time period suggests it probably isn’t. I’ve seen reasonably similar items that serve this purpose.