These fragments of broken pottery are from the Hopi Indian Homol'ovi settlement in what is now Arizona. Archaeologists date their settlement from 1290 to 1400 A.D. They feel there were 4 to 5 villages with the largest having upwards to 1200 rooms. Today where the villages once stood looks no more than this.
One should never remove artifacts from any historical area. Here people have found pieces of pottery and left them on rocks along the trail so as to make it easier for others to see without having to hunt for them. The rocks, someone must have thought were "stone tools".
You can see some pots had a texture to them while others were smooth with a painted design.
I bet the texture aided in holding the pot without it slipping from your hands.
Looks like a bird track on this piece.
I wonder if the Indians had curse words that were muttered when they dropped a bowl and broke it.