It seems I was wrong about the color change being from the gold wearing off. I asked George Wells while at convention about it and he told me that it is a result of the cobalt oxide rising to the surface of the glaze during firing. It did not turn to gas/aerosol due to the temps not being hot enough so it stayed and cooked onto the surface. This will not come off and if you try to remove it you will damage the glaze. It is not a perfect piece, but it still is an excellent piece. This is factory and is not considered damaged. Sorry for my earlier error.