Knox Mason Quart Jar Value Guide

The Knox Mason Quart Jar is a quintessential piece of mid-century Americana, manufactured by the Knox Glass Bottle Company between 1940 and 1955. These jars are highly collectible for their distinct square-shouldered design and the iconic embossed logo that pays tribute to Pennsylvania's heritage as the Keystone State.

What affects the value of Knox Mason Quart Jar?

• Condition of the glass, specifically the absence of 'sick glass' cloudiness or chips on the rim.
• Presence and condition of the original aluminum screw cap, as replacements decrease historical value.
• Clarity of the embossed 'K' and keystone logo, with sharper strikes commanding the higher end of the $10-$15 range.
• Regional demand in Pennsylvania and the Northeast where the Knox brand holds significant local historical interest.

How to Identify Knox Mason Quart Jar?

• Look for the embossed 'K' centered inside a keystone shape on the front of the clear glass.
• Verify the square-shouldered profile which distinguishes this era from earlier rounded versions.
• Check for the original aluminum screw lid, which was the standard closure for this 1940s-1950s production run.
• Inspect the base for specific glass manufacturer marks associated with the Knox, Pennsylvania plants.

History of Knox Mason Quart Jar

Manufactured by the Knox Glass Bottle Company, which was founded in 1917 in Knox, Pennsylvania. The company became a significant competitor to Ball and Kerr, known for their distinct 'K in a Keystone' trademark which paid homage to Pennsylvania's nickname as the Keystone State. These jars were staples in American kitchens for preserving food through the mid-20th century.