Backstamps
A backstamp is a mark on the bottom of the pot. There have been six stamps used over the years, all using the word "Hall". The earliest stamp, dating from 1903-early teens, is in the shape of a teapot with the words "Hall China." If the stamp is a simple circle with the words "Hall's China" and sometimes the notation "Made in U.S.A.." it dates from the 1920s. A plain circle with just the word "Hall" denotes that it originated from the 1930s through the 1970s. A slightly oval shape with the word "Hall" has been used from 1972 to the present day.
Shape of Teapots
The shape of the teapot is also important when dating Hall teapots. Most teapots were made to match Hall's dinnerware patterns. A complete list of the 37 various dinnerware patterns and their years of production, found in a Hall's resource book or on Hall's website, can be quite useful in dating a Hall teapot. Novelty pots were also produced in limited runs and are highly prized by collectors. Their shapes can resemble automobiles, doughnuts and bird cages, among others.
Colors &Sizes
In addition to the various shapes, teapots were produced in 24 different colors and in various sizes. Colors range from cream and yellow to brown and gray, with a wide range in between. The Boston Teapot is one of the original pots selected for sales in a retail outlet and ranged in size from one to eight cups. The Los Angeles Teapot was introduced in 1926 and continued to be produced until the late 1960s. This popular model came in sizes from four to eight cups.
Oddities
Some of the Hall teapot products have an embossed "Hall" logo. Some pieces do exist that have no backstamp at all. These pots were usually factory seconds and were meant to be destroyed but were purchased by company employees at the factory second store, called "Hall's Closet."