No, it doesn’t mean that your jewellery is faulty, or that it is not real silver. If your jewellery has changed colour and has become black, it has oxidised.
Oxidisation, also known as tarnishing, is a natural process for your jewellery to go through and is a product of chemical reaction that is caused by the other metals that are mixed with the silver, reacting to natural and synthetic chemicals in the air and on your skin.
Your body chemistry can affect how quickly your jewellery tarnishes, which is why some people can wear earrings for years with no tarnishing, whereas other people can experience tarnishing of earrings after only a week of wear.
Why does jewellery oxidise?
There are many reasons why jewellery oxidises, and certain things can make jewellery oxidise faster.
Cosmetics
Cosmetic products such as lotions, perfumes, hairspray and makeup often contain chemical compounds which are harder than jewellery itself, causing tarnishing to occur. When wearing jewellery where cosmetic products may be, ensure to use soap and water to clean the area of product before wearing your jewellery.
Moisture
Moisture on the skin, and in the air, can react with the copper present in sterling silver jewellery causing discolouration. This is why it is recommended that you remove jewellery before showering and before doing exercise.
Sulphur
Silver is very reactive with sulphur and produces a surface tarnish, silver sulfide. It is advised that you avoid wearing your jewellery in heavily polluted environments, when handling coal or oil, and when preparing foods containing sulphur such as onions, fish or eggs.
How to remove tarnish from silver jewellery
All is not lost when your sterling silver jewellery tarnishes, it can easily be removed and polished back to its original state. Use a polishing cloth to gently remove the black from the item. If the tarnishing is bad, you can also use some silver polish, such as Silvo, to help remove the tarnish and bring back shine.
When you remove your jewellery, it is a good idea to wipe it down to remove it of any moisture and chemicals from your skin. Store your clean sterling silver jewellery in a dry airtight container or small ziploc bag with all the air squeezed out of it. You can also purchase anti-tarnishing ziploc bags if you want to take extra precautions.