I buy those for my (old Canadian size canning jars that aren't made anymore) Gem jars.ORChick said:Great find! Lucky you!
I have found the rubber rings for the old glass top jars at a local hardware store. Its a Canadian company - Viceroy Rubber and Plastics Limited. I have a few of those jars (just a few, alas!), and also use them for dry storage.
The Gem rubber rings are 78mm, are these the same size as your jars or are yours standard regular/wide mouth jars? If they are standard mouth jars you could always get the rubber rings from Tattler

. My answer was in my best Jeff Woxworthy voice. Why yes I am!!
. When we cleaned out the old wood and storage sheds, we found some stuff in a broken pile under the way-back of the workbench. In the pile was a bunch of rodent evidence, old rusty something-or-others, and a few of these jars. Most of them were broken, but I found three jars and three of the glass lids. They are blue-tinted with very bubbly glass.
I have a "thing" for old mason jars. Have you found a source for the seals? I think lehmans has the old style rubber ring seals... I'm sure other canning supply places have them too.