However, those bronzes unearthed from Lo Yang and ruins of the Shang dynasty, as a whole, are not preserved well with many layers of bronze rusts as well as complicated resolution of bronze character. Humid places suck as the Yangtze River area have an extremely serious erosion phenomenon. Some bronzes even have only one finely thin layer left. This kind of situation is called semi-bodiless or bodiless. Under this type of circumstance, bronzes are difficult to preserve.
Bronzes are alloys of copper, tin and lead.
Striped or spotted streaks appear on the surfaces of the bronze objects after mineralization underground for a long period of time. There is absolutely no doubt about those bronzes with obvious streaks on the surfaces because fake bronzes can never have such patterns. As bronze objects used to be utilized frequently in ancient times, their surfaces are usually quite shiny and clean, especially for those small containers and vessels applied in the ordinary life. When bronze objects are eroded and the texture turns into carbonic copper, luster on the surface will become more compact, which forms an optical film. The optical film has various colors, such as green, black, silver and gold, etc.