Another strange shader

Can someone do something similar?
Circle

Unless you can describe how it interacts with light (does it do anything special), we can’t really suggest methods to recreate it in Cycles (outside of creating a texture plugged into the Principled Shader).

Mother of Pearl (Nacre)? Effect called iridescence, caused by thin-film interference.

check thread: Cycles PBR thin film interference and metals

Yes, something like Nacre. That’s what I try now. But my problem is the pattern.

See also here for a node-based implementation supporting GPU. The pattern you can get by plugging in a noise texture (or any other you like) into the thickness input of the material (either the OSL or the node solution).