shaders - Weird shadow colors / saturation in a Copper material (Principled BSDF) - Blender Stack Exchange
texturing - Copper texture with oil stains cycles material - Blender Stack Exchange
Blend Swap | Metal Materials Pack for Cycles
Old Copper material for Blender (no UV's needed) by Nikola3D on DeviantArt
I'm kind of stuck with this oxidized copper material. I think the normals of the oxidization are the weakest part. Any tips would be greatly apprecia : r/blender
ArtStation - PBR texturing examples in Blender 3D Cycles
ArtStation - Procedural Copper Material (Blender Tutorial)