When you think of archaeological artifacts, what do you think of? Caches of coins? Swords caked in mud? Crystal skulls? Well, while all those things are definitely exciting, they are not exactly common. One of the most frequently-found types of artifacts recovered from archaeological sites are actually ceramics. Ceramics, or objects made out of clay, can be found all over the world and are one of the most important ways we can learn about the past. Even today, ceramics are a part of daily life–maybe right now you’re drinking your coffee out of a ceramic mug.
But, what exactly are ceramics? To make ceramics, you expose shaped clay objects to super high temperatures, like in a kiln, which makes them hard and durable. There are many different types of ceramic that vary based on factors like the type of clay and firing temperature. Common ceramic objects that archaeologists often find include pots, jugs, amphorae, plates, bowls, pipes, and, my personal favorite, pipkins.
There are two parts to ceramics; the “fabric” and the “glaze.” The fabric refers to the main part of the ceramic made of clay. It’s usually grey, white, or pink in color, and may include a “temper,” or another material mixed in, like sand or shell. The glaze refers to the color on the surface of the ceramic. Not all ceramics have a glaze, but the ones that do may have a variety of colors, like green, yellow, black, red, or mottled.
Like many other archaeological finds, ceramics we recover are usually broken. That’s okay, though, because the clay does not decompose easily. That means these objects can remain in the dirt for hundreds, or even thousands of years, virtually unchanged, even if they just look like broken bits.
Ceramics as a dating tool
One of the major reasons that archaeologists love ceramics is that we can use them as a dating tool. No, not that kind of dating. We look at the decoration, materials, and shapes of ceramic vessels, which often changed over time. By studying these changes over time, and correlating them with time periods, archaeologists can create timelines based on the types of ceramics they find. This is a method called seriation.
This has been a really useful method for many sites across the world, particularly in the American Southwest. The Pueblo people have a millenium-long history of creating beautiful ceramics with intricate designs that changed over the years. By carefully studying and documenting the designs from ceramic pieces found at hundreds of sites, archaeologists have been able to identify which designs are characteristic of what set of years.
In other cases, certain types of ceramics were only produced for a specific set of years. Take Borderware, for instance. This post-medieval type was only created in workshops on the border of west Surrey and Hampshire county in England during the late 1500s and very early 1600s. Therefore, if archaeologists find Borderware, they know that the site dates to the late 1500s or later. Borderware also happens to be one of my favorite ceramic types!
Seriation is a relative dating technique because its trying to create a sequence that relies on a ceramic’s relation to another ceramic. There is also absolute dating, which doesn’t rely on such relationships and pinpoints dates by scientifically analyzing specific properties of a ceramic.
For example, thermoluminescence dating uses scientific tools to measure the amount of energy trapped within microscopic minerals of the clay used to make ceramics. This relies on the principle that when certain minerals are exposed to heat–like in a kiln–they trap electrons. Scientists can reheat ancient pieces of pottery and measure the energy that is released. Based on metrics discovered through experimentation, archaeologists can figure out how old a ceramic is based on the amount of energy released when they expose it to heat in a laboratory setting.
As an example, archaeologists working in Bo Yang, Thailand used thermoluminescence dating to determine the age of the iconic Old Historical Wall. The archaeologists knew that the wall was likely built sometime in the mid-1800s, but used thermoluminescence on some brick rubble to determine that the Old Historical Wall was built between 1827 and 1841.
Ceramics as insight into people’s lives and livelihood
Another reason why archaeologists love ceramics is that they can tell us about people’s daily lives in the past, like what they were trading, what technology they used, and what food they ate. Sometimes archaeologists find pieces of ceramic that they know were not produced in that area, which can signal that these ancient societies traded with people outside their vicinity. Perhaps across long distances–often even across oceans.
Archaeologists working across East Africa have found distinctive Chinese-made ceramics at sites from as long ago as the 9th century. They found that Chinese ceramics were highly valued, and that wealthy East African merchants saw them as powerful status symbols.
Ceramics can also tell us a lot about what people were eating. People often stored and served food in ceramic containers, and sometimes molecules from that food became embedded into the surfaces of the ceramics themselves. Archaeologists can then conduct scientific analyses to figure out what kind of food was inside of those vessels. For example, archaeologists working at a 15th and 16th century site in Puerto Rico analyzed ceramic pots and jars to find that people were eating a mix of Spanish foods like olives and wine, alongside Indigenous foods and plants like corn and cassava.
How ceramics tell us about larger social values
Sometimes archaeologists love ceramics because they can help us uncover how people in the past understood the world around them. The patterns and imagery on some ceramic vessels depict abstract or symbolic designs. In some cases, these represented spiritual beliefs. For example, archaeologists have studied axe, horn, and ox designs on Bronze Age Minoan ceramics alongside myths to better understand the ritual and religious aspects of ancient Mediterranean life.
While it can be hard to really know what anyone hundreds or thousands of years ago was thinking, these kinds of artifacts can give us a peek into the minds of people of the past. Ceramics may also provide a way for archaeologists to understand social values. An example of this actually comes from the modern day. An artist named Michelle Erickson had an exhibit at the Baltimore Museum of Art which explores her American and Middle Eastern identities alongside the dark histories of the United States. She draws inspiration from historic ceramics, like an 18th century English jug with the image of two boxers, and crafts her own jug with images of Colin Kaepernick and an enslaved African woman to make a statement about the historical origins of modern racial inequality. This kind of art combines the ancient technology of ceramics with popular colonial-period forms and glazes to then reimagine it to symbolize the experiences of people in the present day.
BONUS: An Abbreviated Guide to Historic Ceramics
As a historical archaeologist, I have had many encounters with different ceramics. Historical archaeologists–or those working at sites from the past 400 or so years–rely heavily on ceramics because they are abundant and easy to date. Most of these types were manufactured in England, but some were made in the Netherlands, Germany, Portugal, Spain, or China. Here is a super short crash course on some common historic ceramic types.
EARTHENWARE: This type tends to be porous and is fired at relatively low temperatures. Sometimes earthenware vessels are glazed, but often not. “Utilitarian” vessels, like un-fancy pots or jugs, are often earthenware. Modern red flower pots are a good example of earthenware. There are two main types of earthenware: coarse and refined.
Coarse earthenwares are fired at the lowest temperatures and are often quite porous, meaning they absorb liquid. Common examples include redwares, North Devon ware, and Borderware.
Refined earthenwares are fired at a higher temperature and are harder. They are often more decorative than their coarse counterparts. Common types include creamware, whiteware, and Tine Glazed.
STONEWARE: Stonewares are fired at a much higher temperature than earthenwares, resulting in an extremely hard ceramic that is not porous at all. Stonewares are often fired with salt, resulting in a pitted, orange-peel-like surface texture and are often in muted tones like tan, brown, blue, and grey. Stonewares were often used for storage, including vessels like jugs, pitchers, or large bowls.
PORCELAIN: Porcelains are fired at the highest temperatures, resulting in a very smooth, fine, white ceramic. Until the 1800s, porcelain was only manufactured in China. Porcelain was often hand-painted and made into beautiful vessels meant to be seen, like tea cups, plates, and figurines.
For more, take a look at these sources:
Ceramic Analysis - Process of Archaeology | UW-La Crosse
The transmission of pottery technology among prehistoric European hunter-gatherers | Nature Human Behaviour
Studying Long-term Patterns of Bering Strait Cultural Interaction and Exchange Through Archaeological Ceramic Analysis
Surrey-Hampshire Borderware | Historic Jamestowne
Telling Time for Archaeologists
Thermoluminescence Dating - YouTube