Where is Clay Found?

Where is Clay Found?

When I first went looking for native clay it seemed to be a rare thing, like gold or silver, I couldn’t find wild clay anywhere. But I knew that it had to be much more common than it appeared because ancient people made pottery wherever they lived. So I did a little bit of research to identify where clay is found and now that I know where to look and what to look for I see clay everywhere I go. So now I am sharing the results of my research with you, keep reading to learn where clay is found.

Because they are the smallest particles of soil, clay particles stay suspended in water longer than sand or silt particles. This tendency to stay suspended in moving waters and to settle slowly in calm water allows clay to form beds where water sat still at some time in the distant past. As a result of this the best place to find clay are along floodplains of rivers and streams or on the bottoms of ponds, lakes and seas. Even if these features existed millions of years ago, long after the water is gone the clay will remain where it was left behind. 

Finding clay often requires a lot of hiking, climbing and exploring so be ready to get outdoors and get some exercise. You may find it helpful to consult geologic maps or Google Earth in order to locate potential areas nearby to look for clay. You will want to bring something to dig with like a shovel or a rock-hammer and something to carry clay in such as a bucket to zipper bags. Trying to find native clay in your area will be an adventure to remember.

Finding Clay in Alluvial Deposits

Clay that is deposited by rivers or steams are called alluvial deposits. These clay deposits do not need to be near a river since the clay could have been deposited by a a river millions of years ago. Still if you want to find clay, near a river is good place to begin searching. The clay could be at the surface or it could be many feet below the surface, so a place where the river floodplain has cut into is the best place to look for clay. Places such as road cuts or where a steam has cut a deep channel are great places to look because they can expose layers of ancient alluvial deposits. Much of what you will find in alluvial deposits are not clay at all, sand, gravel, silt and loam are all common in floodplains so you may have to do a bit of exploring and testing to find good clay.

Along river banks is a good place to look for alluvial clay.

Finding Clay in Marine and Lacustrine Deposits 

Marine and lacustrine are deposits left by seas and lakes respectively. Obviously you aren’t going to put on scuba gear to look for clay under water so in this case you are going to look in places where bodies of water existed long ago so these deposits could be practically anywhere. Some may be seen in hills and others may be below the surface of dry lake beds, road cuts are some of the best places to find clays because they expose layers of ancient ocean strata that might otherwise be hidden beneath soil or vegetation.

Marine or lacustrine deposits are usually recognizable by layers of colorful strata such as those seen in the Grand Canyon. Like any other sedimentary deposit, not all are clay, many are sand, gravel, limestone or other types of marine or lacustrine deposits. So you will need to explore and test out the different layers to see if any are clay.

Digging lacustrine clay from a dry lake bed.

Other Types of Clay Deposits 

Another type of clay that is fairly common are primary clay deposits. These are clays that are in the location where they are weathering from their parent rock, where stones are slowly being formed into clay. These clays are usually mixed with other materials such as rocks and sand. The processes that form alluvial, marine and lacustrine clays, suspending the clay particles in water, purifies and concentrates clay, primary clays have not been subject to these processes so they may require more work to make usable.

The last clay type I will cover are glacial clays. Even if there currently are no glaciers where you live, there may have been during an ice age long ago.

As glaciers drag across the bedrock they create clay by abrading the stones info fine clay particles. This clay is left at the bottoms of glacial valleys after the glaciers melt or retreat.

Glacial and primary clays are not stratified the way alluvial, marine and lacustrine clays are. They both are often found at the surface, at or just below the topsoil. Sometimes they can be located by looking at car tracks on a dirt road, the places where the roadbed is most sticky and slippery is likely an area rich in clay. In dry earth a cracked texture such as that seen in the bottom of dry mud puddles may indicate clay at the surface.

Students digging clay from an arroyo bank in Arizona.

Processing the clay you find

Once you find clay you have some more work to do before you can use it to make pottery. There are two main ways to process native clays, dry process and wet process.

Dry Process – In this process the clay is dried fully, then ground into a powder. The powdered clay is then mixed with between 12% to 25% sand depending on the natural qualities of the clay, this “temper” will help the clay to dry without cracking.

Wet Process – With this process the clay is put in a bucket and covered with a quantity of water, after several days it is mixed up into a this slurry and poured through screen to remove large chucks, rocks and sticks. If there are a lot of impurities in your clay you may need to do this several times using finer and finer screens. Now you need to remove the excess water, let the clay settles and then pour the water off of the top, then pour into a pillowcase and allow to dry out for several days. Once you have a workable consistent knead into your clay 12% to 25% sand to allow it to dry without cracking.

Now your clay is ready to use, have fun making pottery with your homemade, native clay. You have bragging rights to your pottery friends and your art will have a unique connection to the land.

Damp clay and sand ready to be mixed together

Learn More

Hunting clay is something I have enjoyed doing for most of my life and I have been known to stop my car at almost any time and any place if I notice some telltale signs of clay out of the window. This article has dealt with answering the question “where is clay found” but it does not get very deeply into what clay looks like in the wild, how it can be tested or how to process it once you find it. If you are interested in learning more about finding and processing native clay then you may enjoy my online video based class called Native Clay 101. There are also some videos related to finding clay on our YouTube channel here.

I've been making primitive pottery since I was a teenager in the 80's. My work focuses on reproducing the polychrome pottery styles made in the American Southwest during thirteenth and fourteenth centuries. I have taught workshops and lectured at venues all over the Southwest. When I was learning to make pottery it was very hard to find the information I needed, so I created this website to make the technology of southwest pottery readily available to all.

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