Air and reaction with sulfur
The blackening of silver like the appearance of rust on iron. Corrosion occurs as the result of the oxidation, because oxygen in the air reacts with the top layer of iron. But silver doesn't rust. It dims due to formed it of plaque. This dull layer appears when the particles of sulphur in the atmosphere, come into contact with silver.
In the Earth's atmosphere is present in the sulphuric gas, which becomes sulfur dioxide pollution of the environment.
Other causes of darkening of silver
Some Soaps include sulfur components. If you do not remove the silver chain while washing dishes or hands, the silver has a chance to darken.
Magnesium sulfate is sometimes contained in groundwater.
In some areas of the earth Epsom salt chemically reacts and is converted to hydrogen sulfide. Then the gas can rise out of the ground.
In some cases, the silver reacts with the skin of the person who wears it. The chemical composition of the skin of individual people does not allow them to wear silver on your body, because the reaction is very fast. As a result, the skin is painted a dark color and silver dark.
Perfumes, lotions and hairsprays will also react with silver. Metal tarnish from contact with wool, gloves, latex, skin, fat, ammonia, chlorinated water. Some kinds of food also cause a chemical reaction. The metal will change color, if you often eat onions, mayonnaise, salad dressings, eggs and salty foods.
How to prevent the blackening of silver
Sooner or later silver will darken. It is his nature. To silver longer retain the white color, it should be protected from moisture, do not wear every day, don't brush too hard.
In modern production applied rhodium, whereby the silver longer retains gloss and color. While jewelry is coated with a protective layer of rhodium or a special type of silver. While this layer will not be erased, the product will look good and will not blacken.
Silver jewelry should be stored in bags made of polyester. After wearing the silver should be washed with warm water and wipe with a clean cloth. This will slow the process of darkening. You can store your silver with chalk, which absorbs toxins.
To clean blackened silver need a special solution or cloth to clean the silver. Hoping that silver can turn white, it is clean different materials at hand. Do not use silver Polish toothpaste. Its components are too harsh for silver, and this cleaning will do more harm than good.