Why does sterling silver jewellery tarnish?

​Sterling silver is a timeless material beloved for its beauty, durability, and versatile use in jewelry, flatware, and decorative pieces. However, one of the most common frustrations for owners of sterling silver items is tarnishing — when silver turns dull, discolored, or even black. If you’ve ever noticed your favorite silver necklace losing its luster or turning a murky shade, you're not alone. So, what exactly causes sterling silver to tarnish, and why does it sometimes go black? Let’s dive in and explore.
What Is Tarnish?
Before we get into the causes, it's important to understand what tarnish is. Tarnish is a thin layer of corrosion that forms on the surface of silver (and other metals) when it reacts with certain chemicals in the environment. The result is often a dull, grayish, or yellowish film that can obscure the natural shine of the metal.
Sterling silver is an alloy composed of 92.5% pure silver and 7.5% of another metal, usually copper. This combination gives sterling silver its strength and durability, but it also plays a significant role in tarnishing.
1. Reaction with Sulfur Compounds
One of the main culprits behind silver tarnishing is sulfur. When silver is exposed to air, it reacts with sulfur compounds present in the atmosphere or in other everyday substances. This reaction results in silver sulfide, a black compound that causes the metal to turn black. These sulfur compounds are commonly found in items like:

• Air pollution: Industrial areas or cities with high pollution levels often contain sulfur in the air.
• Personal care products: Products like lotions, perfumes, and hairsprays can leave behind sulfur or sulfur-like compounds that accelerate tarnishing.
• Foods: Foods like eggs, onions, and garlic are sulfur-rich and can cause silver to tarnish more quickly when stored nearby.

2. Moisture and Humidity
Another factor that contributes to tarnishing is moisture. When sterling silver is exposed to high levels of humidity or direct contact with water, the surface of the silver can react with the moisture and form tarnish. Over time, this tarnish can become more severe, especially in areas with persistent humidity, like bathrooms or coastal regions where salty air can speed up the tarnishing process.
3. Oxygen Exposure
Silver naturally reacts with oxygen in the air over time, forming a thin layer of tarnish. This is why even pieces of sterling silver that are kept in storage or not regularly worn can eventually develop tarnish. While this process is slow, continuous exposure to oxygen, especially in the presence of other chemicals, will eventually lead to tarnishing.
4. Skin Contact
Your body’s oils, sweat, and even the acidity of your skin can also contribute to tarnishing. Acidic skin or the natural oils produced by your body can create a chemical reaction with the silver over time, leading to tarnish buildup. This is why sterling silver jewelry, such as rings and bracelets, can tarnish more quickly when worn regularly, particularly for those with more acidic skin.
5. Storage Conditions
How you store your sterling silver pieces can also play a significant role in how quickly they tarnish. Storing silver in open, humid spaces or in places where it's exposed to air, light, and moisture can speed up the tarnishing process. Additionally, placing silver jewelry in contact with other jewelry, especially metals like copper or brass, can result in a reaction that causes tarnishing.
6. Chemicals and Cleaning Products
Another major factor is chemical exposure. Household cleaners, bleach, or even chlorine from swimming pools can cause silver to tarnish. Overexposure to chemicals like these can speed up the tarnishing process or even damage the surface of the metal, especially if silver is cleaned improperly.
How to Prevent Tarnish on Sterling Silver
Now that you know what causes sterling silver to tarnish, the good news is that there are several ways to keep your silver looking shiny and new:

1. Store Silver Properly: Keep your sterling silver jewelry or items in a cool, dry place, ideally in an airtight bag or box. Anti-tarnish pouches or cloths can also help prevent tarnish buildup.
2. Wear Silver Regularly: Wearing your silver regularly can actually help prevent tarnishing since the oils from your skin can keep the silver’s surface protected.
3. Clean Silver Often: Gently clean your sterling silver items using a soft cloth and silver polish. Regular cleaning can prevent tarnish from building up over time.
4. Avoid Exposure to Chemicals: Remove your silver jewelry when using cleaning products, swimming in chlorinated pools, or applying perfumes or lotions.
5. Use Anti-Tarnish Products: There are plenty of anti-tarnish sprays, cloths, and dips available that can help protect your silver from tarnishing.

In Conclusion
Tarnishing is a natural process that occurs when sterling silver reacts with sulfur, moisture, oxygen, and other environmental factors. While it can be a bit of a hassle, with proper care and maintenance, you can keep your silver items looking their best. Regular cleaning, careful storage, and avoiding exposure to harsh chemicals can go a long way in preventing tarnish and keeping your silver gleaming for years to come. Whether it's a cherished heirloom or a newly purchased piece, sterling silver will continue to shine — with just a little attention