“A vessel is formed from a lump of clay with care, however, it is the empty space within the vessel that makes it useful.”
– Lao Tzu, Dao De Jing
What are pottery and ceramics? Is there a difference? Is everything that is made out of clay pottery? Are all ceramics made out of clay?
They have been around for a long time…
Pottery and ceramics have been an important part of human culture for thousands of years, as the figure of theVenus of Dolní Věstonice attests to. It is the oldest known ceramic object in the history of mankind, dating to about 29,000 BCE.
Ceramic objects are probably the first durable invention of humankind as they do not degrade as easily as other organic materials. China has the honour of producing the first ceramic vessels known to date to around 16,000 BCE.
By 5,000 BCE, the Egyptians were mass producing pottery, although this was documented only much later, as the wall paintings at the tombs of Beni Hasan show.
In its most basic forms, the words ceramics and pottery both refer to the same thing: an object made of clay and hardened by heat, in a process called firing or baking. Ceramic objects include both decorative and practical, utilitarian items.
Ceramics and pottery are also used to refer to the processes involved in making such an object. As such, pottery is both an art and a science – an artist’s eye and hands are required for fashioning an object of beauty, while a scientist’s precision is needed for controlling the different operations.
How do we make them?
There are four steps needed to make a pottery product:
1. Preparing the clay mixture
2. Shaping or fashioning the clay
3. Decorating and glazing the item
4. Firing or baking in a kiln
More details on each stage will be provided in future articles, but you can start reading on the first step, “Clay”, to understand more about clay mixtures and bodies.
Are there different types?
There are three broad categories of ceramics: earthenware, stoneware and porcelain. Each type is distinguished by its clay mixture and the temperature at which it is baked or fired.
A fired piece of pottery is called matured. This process transforms the clay – where a dried clay object could still disintegrate (slake down) upon contact with water, the heat permanently alters the chemical composition of the clay so that it retains its shape and will never dissolve in water again.
• Earthenware is a pottery clay mixture that is fired at a low temperature, from 400 to 1000°C (or 752 to 1832°F). At around 1000°C the clay molecules begin to fuse.
• Stoneware is made of a heavier clay mixture that gives it greater strength. As a rough guide, they are fired from 1100 to 1300°C (or 2012 to 2372°F). These high temperatures makes the clay become vitrified, or glassy. The strength of the pottery is increased as it turns into a solid mass.
• Porcelain is the purest and most delicate type of pottery, made from a fine white clay known as kaolin. Porcelain requires high temperatures for maturing, from 1200 to 1400°C (or 2192 to 2552°F).
What’s so interesting about them?
For archaeologists, anthropologists, and historians, the study of pottery can help to provide an insight into past cultures because of the durable nature of pottery. Fragments can survive long after other artefacts made from less-durable materials have decayed beyond recognition.
Combined with other evidence, the study of ceramic artefacts can help us gain insight into the organisation, as well as the economic, cultural, religious and social conditions of past societies.
Where these ancient societies did not have writing systems and therefore written records of their history, chronologies based on pottery are helpful for dating them. In addition, chemical analyses of trace elements in ceramic fragments can help identify sources of clay and hence the networks of trade and communication that linked neighbouring cultures.
Front view of museum reproduction of the Venus of Dolní Věstonice
Ancient Egyptian potters depicted in a wall-painting as they wedged, formed, and fired their wares. From Tomb 2, Beni Hasan, c. 1900 BCE.
Egyptian Making Pottery, With Furnace Beni Hasan, 1900 B.C.E.