Although the physical and chemistry performance of noble metal is very stable, ornaments made by noble metal would become dinginess and roughness after people weared and kept them.

• 虽然贵金属的物理化学性能都很稳定,但在日常复杂的佩戴、收藏环境,依旧会受到腐蚀和磨损,使其表面变得暗淡,粗糙。