Native Clay Hand Preparation

This clay has fallen off the overhang and landed in the stream below. A mineral in the clay has oxidized and turned an orange-yellow on the outer surface. The unexposed clay is a uniform medium grey.

This is where you can observe the layering of the earth: coal, slate, clay and soil. All on top of a nice sandstone bedrock. This stratification occurs under our feet, but water erodes the land away to expose the layers. Just because you don't see the clay, or can't find it at the depth you dug, doesn't mean it is not there under your very nose.

Materials and equipment:
• shovels - round and sharp • gloves if you want
• old shoes, boots, waterproof is ideal
• buckets for hauling the dig
• notebook and pen for documenting the collection site
• ziplock baggies and marker for collecting smaller samples
• usual hiking gear (water, insect repellent, sunscreen, etc.)

Clay is usually near water. Streams and rivers cut into the land, exposing the clay. A good indication of high clay contents of soils is cracking when dry. Beds and shores of rivers usually show evidence of clay deposits. Hillsides with their valleys, and everywhere that was once underwater millions of years ago should have a clay bed. The pure part of the claybed is called the vein. Major clay refiners mine their materials from these pure veins. Pure clay is nearly uniform in color.
You can test for clay content in a soil sample in the field.

Moisten the sample. Try to roll it into a coil (tube) with your hands. If it sticks together nicely, even when you bend it, the clay content is high.

Be sure to avoid gathering too much organic material when getting a sample. Usually the clay is beneath a layer of topsoil, so dig several feet into the surface. Be sure not to contaminate the sample with gravel if digging roadside, the limestone will explode in the firing. Natural lime deposits and lime runoff from agriculture applications can cause lime popping - small explosions in the clay during firing.