Find the age of old Ball jars by examining the logo, and find the age of glass bottles by examining symmetry, mold seams, suction scars and color. Embossed lettering may also aid in the dating of glass bottles.
If a Ball jar has an overlapping logo with the letters BBGMC, which represent Ball Brothers Glass Manufacturing Company, the date range is 1885 to 1886. Jars with the word "Ball" in block letters are dated from 1895 to 1896, and those with a horizontal script logo are from the same time period. All other script logos are from 1900 to 1960 unless the loop of the B is closed, which signifies a jar made after 1960.
Glass bottles made before 1850 are often asymmetrical due to being hand-blown, and they often have an irregular bottom indent and no mold seams. Bottles made from 1820 to 1910 may have no pontil mark and side seams that disappear at the neck. Bottles made after 1910 are machine-made and have mold seams that reach to the lip, uniform thickness and a perfect suction scar. Embossed lettering came about in the late 1800s, and glass with a blue or purple tint is likely from the late 1800s to the 1920s.