The rocks range from small to very large and can be dug out of the old mountains where no road or town has ever been. And there are lots of them scattered about as the earth washes off of them. Most have not been broken and look like a squarish or rectangular blocks of stone two feet square. Here is another one that has a smaller opening. I have soaked most of the clay out.
Definitely not man made. definitely rock. The best ones I find have one entire side open. The clay is as fine as baby powder but soaks to complete liquid. I would like to get the bigger ones but it is all I can do to collect some of the smaller ones and trek them out of the hills. Besides I do not know how to break the stones open anyway.
