Strange mason jar?

[smoke7278]

Curious about this mason jar. Has original glass insert in original zinc lid. Haven't been collecting long but haven't seen one with such a square "shoulder". Any info much appreciated as I'm learning!

 

[Sitcoms]

I'm no mason jar expert, but this one is a Mason's Patent fruit jar. I'm not sure on how to date these - they were made for a long time in much the same exact way with the same embossing from what I understand. The squared off shoulders were needed to put the threads on the jar and so the top would seal evenly. You can read more about these here: https://fohbcvirtualmuseum.org/galleries/jars/masons-patent-nov-30th-1858/

It's interesting that the zinc top is Ball brand. I'm not sure if the Ball Brothers made tops for other companies or if yours is a later replacement for the jar.

 

[Newtothiss]

Sweet