The fact that a silver jewel loses its initial brightness and becomes blackish, is something completely natural, you should not be alarmed or think that the piece is of lower quality, since this happens even to the pieces of greater purity .
This is due to a process similar to oxidation called sulphidation. Although silver is a noble metal that does not oxidize, meaning that it does not react with the oxygen in the air, it does with hydrogen sulfide (H2S) equally present in the environment.
Factors that accelerate the process:
You will see that in summer time your silver pieces need extra care, since they are more likely to react and grow dark. Sun and heat speed up the process, because the temperature facilitates the reaction.
The different PH of the skin also have an influence over silver, since there are people who have a more acid PH. Even the use of medications can alter the PH of our skin.
The use of perfumes and lotions also has a direct effect on silver. Also some household chemicals and soaps.
But if your pieces have changed color, the good news are that the process is reversible, so I recommend you consult our section on metal care in which I explain a simple and effective remedy for your jewelry to look like the first day.