What is This Mini Crop Circles ?

[Nyboy]

Crystal formation sounds the prettiest!

 

[so lucky]

In the center of the circle it looks like either an indentation, or a little bump. Could be a piece of something that was in the clay when the pot was made and fired. It would cause a weak spot in the glaze, thus creating what Thistle described.

 

[Nyboy]

Center of circle feels smooth. Was a cheap pot from Christmas store.