A Mason jar is a glass jar used in canning to preserve food. They were invented and patented by John Landis Mason, a Philadelphia tinsmith in 1858. They are also called Ball jars, after Ball Corp., a popular and early manufacturer of the jars; fruit jars because they are often used to store fruit.
The Ball Brothers Glass Manufacturing Company began manufacturing fruit jars in 1884 in Buffalo, New York. After a destructive fire in the Buffalo plant, however, the five Ball brothers and their families relocated to Muncie, Indiana, where their business has become known worldwide.
Mason jars have screw-on rings. The ring holds the lid in place during the canning process, which creates a partial vacuum, sealing the lid until opened.
The Mason jar was also used during warfare. The safety pin of hand grenades would be pulled and the grenades would be placed in glass Ball Mason jars which would hold back the safety lever. The safety lever would release upon the shattering of the jar and the grenade would detonate. This particular improvised explosive device was popular with chopper crews in Vietnam, who would use them as improvised anti-personnel cluster bombs during raids. They were easy to dump out of the flight door over a target,and the thick Ball Mason glass was resistant to premature shattering in the air.
Today they are used for a variety of reasons. They can used for lighting or chandeliers, a vase, food preserver, drinking glass, bug jar, storage jar, ingredient jars, etc.