Among all the clays I have collected from the nature, Straža clay impressed me the most. A bank of freshly dug dirt didn’t looked like much. Truth to be told, what attracted me most was the tiny iron pebbles and larger pebbles of beige and pink colour, which you could break with hand. I could not tell what they were, but they looked attracting. I still do not know, further research or a talk with geologist will be needed. But I am assuming it is a kind of primary clay, clumped and pressed together and obviously rolled through or with something, because the shape was rounded. So I dug together a small bag of it all, mixed with deep red dirt. Later that dirt turned out to be clay as well. I let the material dry for some time.
I soaked the whole content in water. I used finest sieve for separating smallest particles from larger. So I got dark brown-red clay. Secondly I mashed the residue against the sieve with my hand, trying to squeeze few more drops of clay. Interesting thing happened. The beige particles started to break down. But not completely. I separated the beige ‘clay’, mixed with a little brow that has left. So I got sandy coloured clay. I washed and dried what has left. And sieved that to 3 different sieve sizes. The residue had: beige particles, iron pebbles and other rocks, among them I guess feldspar and silica.
Bigger beige pebbles I froze and poured over boiling water. I imitated natural proses of weathering clay. Pebbles broke, but not completely. I sieved that as well.
So I separates irony pebbles, broke down beige clay-ey pebbles, red clay and rocks mentioned before.
After I mixed the different size residue stones to clays again. Results are beautiful!