There are many different ways that we can date a site or specific artifact. We can look broadly at the contextual history of the area, look at how a glass bottle was constructed, or use construction material like nails to create broad date ranges. Specifically with ceramics there are several ways to establish a time frame for the artifact including: paste thickness, decoration style, rim construction, colors used, as well as size and shape. Sometimes we get really lucky, and a ceramic sherd will have a maker’s mark. Most ceramic companies have well documented records for the changes made to their unique marks, making it relatively simple to establish a date range for most marked ceramics. But sometimes with 19th century British ceramics we get every more lucky and can establish the specific date the ceramic was produced on. This occurs when we are fortunate enough to have a British Registered Design mark.
Beginning in 1842 England begin offering “registered designs” for ceramics. This is akin to a patent or copyright trademark today. The ornamental design act of 1842 expanded design protection into new types of materials, such as ceramics. This allowed for manufacturers to protect not only the functional design of their products, but also their aesthetic design as well.
Each of these diamond marks contain very specific information that tells us what class of material the object is, the day, month, and year it was produced, and the bundle number. There are two ways this information can be arranged. The first configuration was used from 1842-1867.
There are published tables that identify what each of these letters and numbers mean. A good example can be seen here, but there are also published books where the same information appears. Based on those tables we know that the ceramic pictures above was produced December 18th, 1856:
- IV = ceramic
- L = 1856
- A = December
- 18 = 18th
- We don’t need to worry about the bundle number
If we were in England we could go to the British Archive and view the specific design that corresponds with this information. However, even without a trip to England, there’s still even more information that this mark can tell us. By knowing the specific date it was produced, you can look this information up in books, and sometimes figure out who the manufacture was of the ceramic. This is useful if you have a sherd that contains a registered design mark, but not lucky enough to have the maker’s mark.
The design changed slightly for ceramics produced between 1868-1883. During these years the arrangement of the symbols changed. The year and day marks have switched places, as have the month and bundle.
In 1884 England switched from the diamond registered date mark to a new registry number system where a numerical mark designated a specific year. Similar to the registered date marks, this information can also be found in published tables. The dates in the tables are the lowest/first number recorded for each year. So for example let’s look at the registered number in the above image, 49221. This number falls between the 1906 number (471860) and 1907 number (493900) so we know it was produced in 1906.
So sometimes diamonds are not just a girls best friend, they’re an archaeologists best friend.