Identification marks commonly found on glass items are the name of the manufacturing company where the item was created, the location of the manufacturing plant and the city of origin. Other marks include trademarks and the name of the brand.
Glass bottles and jars are the most common objects that have distinguishing marks, while other items include tableware and industrial products. In the 19th and 20th centuries, the markings provided a history of the item itself, with the name of the plant and location where the glass item was created etched on the bottom of the object if it was a bottle, or on the front if the item was a jar. Some identification markers are more obvious than others. Manufacturers may have the name of the bottling plant, yet others may just have an identifying number to differentiate one plant from another.