Sterling silver is an alloy. What is an alloy? An alloy is simply a combination of metals. Sterling silver is 92.5% pure silver (hence the “925” stamp commonly found on sterling silver!) and 7.5% other metal, typically copper. Fine silver, which is 99.9% pure, is too soft for practical use; adding copper to it increases its strength and malleability while retaining the desired silvery color. However, copper is susceptible to oxidation and corrosion, which is why sterling silver tarnishes more easily. But what exactly is tarnish? And, more importantly, what causes it?
Tarnish is silver sulphide, a compound formed between silver and sulfur. According to an interview between jewelry designer Zoë Richardson and Better Homes and Gardens magazine, tarnish is “a thin layer of corrosion that forms on metals” that “protects the inner layers of the metal”.
Sterling silver will tarnish more quickly in places with high humidity when there is sulfur present. Silver is a noble metal, which means it is resistant to oxidation and corrosion in moist air. However, moisture and temperature do have an effect on sulfur, and it is the interaction of humidity and sulfur with the silver that causes tarnish.
Contact with moisturizers, perfume, hairspray, deodorant, and make-up can lead to tarnish, as these may contain abrasive chemicals that corrode the silver.
Wearing your jewelry when preparing sulfur-rich foods, such as eggs, fish, and onions, exposes it to sulfur and greatly increases the risk of tarnishing.
The higher the acidity levels in your skin, the quicker your sterling silver jewelry will tarnish. Highly acidic skin is oily, sensitive, and prone to breakouts and redness. Allergies or sensitivities can even cause Silver jewelry to blacken within hours of contact in some cases and the change can be quite severe.
To clean tarnished silver, use a polishing cloth or soak it in a solution of warm water and ammonia and scrub it lightly with a soft toothbrush. It is a good idea to clean your silver jewelry regularly, even if you don’t see signs of tarnishing.
Storing sterling silver jewelry properly is vital in warding off tarnish. Store each piece separately in an air-tight container, such as a Ziploc bag. You may also wrap each piece in a soft cloth, but never newspaper. Small silica gel sachets absorb moisture, so storing those alongside the jewelry is a great additional precaution.
*For pieces purchased from my website, please refer to further cleaning instructions in the following post before attempting to remove tarnish from your piece: