Pure silver 999.9 has almost no impurities and practically does not interact with the environment. But since silver is too soft and non-plastic metal, it is rarely used in its pure form for jewelry. In the manufacture of jewelry, 925 sterling silver is used. A 925 sample is obtained by adding about 7.5 percent of impurities of other metals, the basis of which is copper, to pure silver. It is copper that is subject to oxidation, and it is because of copper that we can observe the formation of a gray-yellow-green coating on silver jewelry. The process of darkening during wear is called «natural oxidation (oxidation)».
The main oxidizing agent is sweat; in addition to salts, it also contains amino acids, which include sulfur. Under the influence of these compounds, silver turns black. This may be due to prolonged increased physical activity, hormonal changes in the body, or from strong emotional shocks, stress and worries.
Tarnishing in the air, even when the product is not worn, is a natural process and depends on many factors:
1. Environmental humidity.
2. The chemical composition of the air in your region, city, house, apartment.
3. Cosmetic and chemical products that you use: perfumes, creams, bleaches, dishwashing detergents, acetone, iodine. Not only these substances themselves, but also their vapors. Once we encountered a situation where the seller forgot an open bottle of iodine on the shelf under the display case, in the morning all the silver jewelry darkened.
4. Not the entire decoration may turn black, but only one side. For example, a silver cross turns black only from the outside. As a rule, the inner side of the crosses is smooth, which ensures maximum fit and limits the access of oxygen. And the more open and embossed side will oxidize more strongly.
5. The product may change color where it comes in contact with clothing.
6. Taking medications can affect the appearance of the jewelry, changing its color, since the components of the drugs, released through the sweat glands, come into contact with the product.
7. Silver can also darken on the windows of jewelry stores, especially those that use lamps that emit heat to illuminate the windows. There is little space inside the showcases, the air heats up quickly and an aggressive environment is created in which silver begins to change its color. More than once we had to observe a picture when the open part of the chain in the window was pale gray, and the closed part remained snow-white.
There are also reasons that you should not talk to a person in the eye, as this can offend or offend him. For example, it is believed that silver is a kind of human health detector. The longer it does not darken on the body, the more healthy the human body. And if the silver turned black very quickly, it means that something is going wrong in the human body. There is an opinion that the darkening of silver jewelry indicates deficiencies in the functioning of the liver and kidneys. But there is no scientific evidence to support this yet. The same doubtful fact is that silver turns black from the accumulation of negative energy. Allegedly, it takes a hit if a person is subjected to damage or the evil eye.
In harmony with yourself, in harmony with you.