Tennessee red clay test firing.

My wife and I went on vacation last week to the mountains of Gatlinburg, Tennessee. I gathered a sample of the well known local red clay to test once I got back home. I wanted to try it out to see how it compared to the clay from my back yard here in Indiana.


The differences in clay is most noticed by color from the iron oxides. Both types have it, but it is more obvious in states of the south. It may have to do with glaciers that overran the northern states like Indiana thousands of years ago.

I brought back several pounds of red clay from my vacation in a plastic tub for test firing.

The outer two are Tennessee red clay and the inner two are Indiana clay. Green unfired from the brick press. The sample clay is very sticky and plastic. It makes a nice unfired brick.

The brick on top is Pigeon Forge, Tennessee red clay. The other three are Flora, Indiana brown clay. Fired in the same kiln for 9 hrs to 1875deg F. Notice the difference in shrinkage.

Heres the address if you are interested in why some clays are so much more red than brown, yellow, or grey.

http://www.ga.nrcs.usda.gov/technical/soils/red.html