Things You'll Need
Instructions
Identify the maker's mark. It is usually located on the bottom center of a dish in an underglaze dark color (often dark green). If a date code is present within the maker's mark, then dating the china piece will be easy. If not, it becomes more difficult as Shenango did not often change the motifs on its maker's marks.
Look for a date code on the maker's mark. Unfortunately, a date is not present on the majority of early pieces (prior to 1950), but if present, it will be a number code separated by a dash in most instances. From 1901 to 1949, reading the date code is simple. The month is represented by a number (1 through 12), then a dash, then the year of manufacture. Thus a code that reads, "6-25," means that the piece was manufactured in June 1925.
Look for a letter as part of the date code. Most Shenango china produced after 1949, has a date code that consists of a letter and number. This code is a little more complex to date and a code chart (such as provided on the Restaurant Ware Collectors Networks website) is needed to interpret the date.
Examine the maker's mark motif if no date code is present. Estimate a rough date from the design and content of the maker's mark. Unfortunately, Shenango's most popular marks, a seated Native American and a Native American portrait in a circle, have been used since 1901 and are not datable.
Look for maker's marks from Shenango affiliates. The major brand is Castleton China, which dates 1940 to 1980. The Martha Washington "States" reproduction china, with the history of the Washington china as a maker's mark dates from 1932. The Inca Ware mark dates after 1935, the Royal Sentinel mark after 1950, and the Crown Boutique mark dates after 1960.
Look for a "Haviland--Made in America" maker's mark. Shenango produced the American line of Haviland porcelain from 1936 through 1958 and used this mark.