Xia mask previously cleaned with removal of the clay and ferruginous crust. The protonated layer and the patina color caused by the clay and ferruginous material in the surface micro pores cannot be cleaned.
Xia mask previously cleaned with removal of the clay and ferruginous crust. The protonated layer and the patina color caused by the clay and ferruginous material in the surface micro pores cannot be cleaned.
Nephrite Jade radix cultura 