Identify date for Kearns Mason Jar

[Soaps by Patricia]

I have a Mason jar that I believe was made by Geo W Kearns between 1860 and 1868. But it could have been in the 1870s by Kearns and Gorsuch. I would appreciate feedback. Here are the identifying marks and photos. I put white paper inside the jar for some of the photos and black material for one photo to get the markings to show better in the photos.

1. This is a photo of the entire jar. It is a quart jar.
2. There are two plain markings on the bottom. The first is a K exactly like the Kearns K used on many of the jars made by various Kearns companies. The second marking is either a 6 or G. It looks more like a 6 when compared to the G used on Kearns and Gorsuch jars.
3 The rim at the top of the jar is clearly glass blown and probably ground. It is not perfectly level.
4. There are ridges/creases on two sides of the jar.
5. There are about 3 imperfections in the glass. I am including one photo of the largest one.
6. The jar is imprinted with the Mason patent. It says “Masons Patent Nov 30th 1858”

The biggest unknown is point #2. Is that a 6 or G? Thanks for your feedback.

 

[jarsnstuff]

Let's clarify a few things. Jars were made with the "Nov. 30th 1858" embossing well into the 1900s - around the WWI era. For the most part, ground lip jars were made before 1900 and smooth lip after. We use that as a rule of thumb simply because of the many glass makers and they didn't all switch to machine made jars at the same time.
The earliest Mason's Patent jars had very square shoulders and we refer to them as Crowleytowns. Those jars gradually morphed into the shape yours has, which would be no earlier than say 1870.
I'm attaching a page from the Standard Reference which addresses the Kearns=Gorsuch Bottle Co. The late Dick Roller did tons of research on glass companies and his work is generally accepted by collectors to be accurate. You will note that he lists the Kearns Gorsuch Bottle Co. as operating between 1895 to the 1900s.
I can't tell you for sure whether the K stands for Kearns, but I am pretty sure that's a 6. The K may or may not be part of the mold identifier, and it may or may not be made by Kearns Gorsuch. That being said, there were many glassmakers and many mold identifiers.