Why does silver turn black? Understanding tarnishing in silver jewellery

Silver jewellery has long been cherished for its elegance and timeless appeal. However, many silver jewellery owners have noticed that their pieces tend to darken or turn black over time. This discolouration, known as tarnishing, is a natural process that affects all types of silver, including sterling silver (92.5% silver). But what exactly causes this, and how can you prevent it? Let’s explore. 

Tarnishing occurs when the surface of silver reacts with sulfur compounds present in the air. This reaction forms a layer of silver sulfide on the jewellery, which appears as a black or dull grey film. While tarnish doesn’t harm the silver itself, it can diminish its beauty and luster. 

Exposure to Air and Humidity: Silver reacts with oxygen in the air, but it’s the sulfur in the environment that speeds up tarnishing. High humidity can also accelerate this reaction. 

Contact with Skin and Sweat: Natural oils and sweat from your skin contain acids that can lead to tarnishing. Daily wear exposes silver to these elements, particularly during warmer months. 

Pollution and Chemicals: Industrial pollution, household chemicals, perfumes, and lotions can all contribute to tarnishing. When silver comes into contact with these chemicals, the reaction can be faster and more intense. 

Food and Sulfur Compounds: Certain foods like eggs, onions, and garlic contain sulfur compounds that can transfer to silver jewellery, causing tarnishing. 

Sterling silver, often referred to as 92.5 silver, is an alloy made from 92.5% pure silver and 7.5% other metals (commonly copper). While pure silver is more resistant to tarnishing, the copper in sterling silver makes it more prone to darkening when exposed to air and moisture. The added copper reacts faster with sulfur and oxygen, speeding up the tarnishing process. 

- Store Jewellery Properly: Keep silver jewellery in airtight bags or containers to limit exposure to air. Anti-tarnish strips or silica gel packs can also help absorb moisture. 

- Polish Regularly: Gently polish your jewellery with a soft, lint-free cloth to remove any tarnish. Avoid abrasive materials that could scratch the silver 

- Avoid Chemicals: Remove silver jewellery before applying lotions, perfumes, or household cleaning products. If you're swimming in chlorinated water, it’s best to take off your jewellery to prevent tarnishing. 

- Wear It Often: Surprisingly, wearing your silver jewellery can actually help slow down the tarnishing process. The oils in your skin can create a protective layer on the surface of the silver, reducing tarnish buildup. 

How to Remove Tarnish 

If your silver has already turned black, don’t worry! You can easily restore its shine at home with these methods: 

Silver Polishing Cloth: Use a polishing cloth specifically designed for silver to remove tarnish. 

Baking Soda and Water: Create a paste with baking soda and water, gently rub it on the tarnished area, and rinse it off with lukewarm water. 

Vinegar and Aluminium Foil: Line a bowl with aluminium foil, add hot water, and mix in baking soda and vinegar. Place your jewellery in the solution for a few minutes. This method causes a chemical reaction that helps remove tarnish.

Tarnishing is a natural process that affects all silver jewellery over time. However, with proper care and maintenance, you can keep your silver pieces looking brilliant and shiny. Understanding the causes and prevention methods will help ensure that your jewellery remains beautiful for years to come.