Digging up my front yard to plant a tomato some months ago, I was muttering to myself that this soil has a LOT of clay in it. Then I picked it up and squeezed it, and nope, it's not kinda clay like, it's CLAY. So I sculpted a tiny sleeping pony with my hands and a twig, then let it bake in the sun and carved into it a bit more with another twig. Figure you can't get much more earthy than that.
Maybe at some point I'll actually separate out the clay from organic matter and do some real sculpts with it and pit fire them. This little guy has so much organic matter in it that I'm guessing it would crack/explode with a firing.