The reason why silver oxidizes is SULFUR.
Sulfur is found in various chemicals, in eggs, in the air, and so on, BUT this does not mean that the ring will inevitably turn black. Under normal conditions of your life, this will happen in 50 years.
So why does it happen faster for some?
Sweat is often the cause. In addition to salts, it also contains amino acids, which include sulfur. Under the influence of sulfur-containing compounds, silver turns black.
Remove jewelry before physical activity. We also advise you to remove rings when working with chemicals, as their composition is different and who knows how they will affect your jewelry.
Following this, we answer the question: "Usually my silver rings that I bought in the store do not turn black, why?" This happens because the products bought in the store are always (!) Covered with rhodium, this is a non-oxidizable metal of the platinum group.
We sell 925 sterling silver rings without any coatings.
There are a lot of instructions on the Internet on how to clean silver at home, but if you are afraid to do it yourself, you can bring the ring to us or any other jewelers for cleaning.