My neighbor ask if I could find out anything about 4 old jars he found. I found out the 3 ball mason jars are from the 1910-1923 era. But I have not had any luck with the green one. The only mark is a thin curved line on the bottom and I believe it was blown. I would appreciate it if someone can help me with that one, and he would like to know if they are worth anything. Thank you for your help.