Ever wondered why your beautiful and vibrant silver rings or bracelet become dull and black and lose their sparkle over the course of time? Ever wondered why antique silver ornaments in your cabinet look so old and tarnished as if they’ve never shone before? If yes, you’re at the right place!
In this post, we’ll tell you why does silver tarnish! Let’s dive deep and study the science behind tarnishing, shall we?
Why Does Silver Tarnish?
Generally, silver reacts with sulfur-containing compounds to form greyish-black silver sulfide, a chief component of tarnish. So yes, even pure silver is not immune to tarnishing when brought in contact with sulfur-containing gases.
However, if you’re handling sterling silver, the 7.5% copper in the alloy makes it more prone to tarnish.
Due to the presence of 7.5% or more copper in sterling silver and other low-purity silver, tarnish layers of these silvers are also found to contain other compounds such as copper sulfide and copper oxide besides silver compounds.
Overall, tarnish results from the oxidation process, where silver and trace copper are oxidized to their sulfides and oxides. Scientists, while studying silver tarnish, have often found silver chloride to be part of the composition.
Among countless chemical processes that occur naturally, silver tarnishing is one of them and, thus, is inevitable. Nevertheless, there are various ways to accelerate or decelerate the rate with which silver tarnishes. We’ll discuss everything in detail below.
The Science Behind Color Changes During Tarnishing
Commonly, silver tarnish is of black color. But when applying patina, especially Liver of Sulfur, on your silver, if you perform with precision and catch the color at the right time, you can witness of range of tarnish colors.
You will notice the color range – straw yellow, red-brown, purple, blue, and finally black. You can witness this color progression in a natural tarnish layer as well, but it might take years to develop.
Now, let’s discuss the science behind changing tarnish colors! The color of the tarnish changes as the tarnishing proceeds due to a phenomenon called ‘Thin-film interference.
The light that hits the tarnish layer splits, where some are reflected from the top of the tarnish, whereas the others are reflected from beneath the tarnish layer. When the light recombines after reflection, some colors are lost.
The colors that remain depend upon the thickness of tarnish, and only when the thickness is greater than 100nm is when the true color of tarnish – black is observed. Below that thickness, you will notice the color of tarnish changing.
How Long Does Silver Take to Tarnish?
The rate of tarnishing tarnishes mostly depends upon two variables – the concentration of sulfur-containing gases that the silver has been exposed to and the length of time of the exposure.
Hydrogen sulfide (H2S) is one of the most common culprits of tarnishing silver. Hard-boiled eggs, as it imparts H2S, are often used to add patina to silver pieces.
As strong oxidants are also known to tarnish silver, how much your silver is exposed to such chemicals also determines the tarnishing time.
If you take silver jewelry to the pool or hot springs, you might notice tarnishing within minutes. But if you store your silver in a cool dark place, away from chemicals and moisture, it might take months or years before you notice a layer of tarnish on such items.
Moreover, the rate of tarnishing is greater in freshly polished silver pieces than in silver pieces that already have a fine layer of tarnish over them. Due to that reason, experts often suggest letting a layer of tarnish sit on top of your silver if you can.
The Factors That Accelerate The Tarnishing Process
If you want to prevent your silver from tarnishing, first, you must know what factors accelerate the process. Here are a few factors that are known to accelerate silver tarnishing.
1. Moisture and high heat
Never soak your silver items in water, and never store them in hot places. Moisture and high heat are known to aid in the tarnishing process. If your silver piece is moist, dry them with a cloth instead of air drying. Remember – air-drying can lead to spots!
2. Some food particles
Foods such as garlic, onion, eggs, black salt, and spinach can accelerate tarnishing. If your silverware has come in contact with any of these, make sure to clean them properly before storing them.
3. Papers, cardboards, latex, and rubbers
These materials are known to have high sulfur content. Paper and cardboard used in the packaging have been identified as one of the most common tarnishing accelerants.
Makeup, hair products, or even perfume might contain chemicals that react with silver and aid in the tarnishing process. Moreover, makeups are also known to contain abrasive materials that rub off tiny metal particles, which then might appear as black dust.
So, always wear your silver jewelry at last, and every once in a while, make sure you clean it with mild soap and water. And dry it quickly using a silver-safe cloth. As we all know, moisture is a big no-no!
Household oxidants like bleaches are also known to tarnish silver within minutes. So, if you’re using bleach for some purpose, make sure you take out your silver rings and bracelet beforehand.
How to Protect Silver From Tarnishing?
Your silver will sooner or later tarnish. But hey, that doesn’t mean you cannot delay the tarnishing process, right? If your silver pieces have a habit of trashing a lot sooner than you expect, this section is a must-read for you. Read on to find out how to protect your silver from tarnishing.
1. Avoid moisture and high heat
Sulfur-containing gases tarnish silver at a higher rate when the temperate is warmer, and the relative humidity is high. So, always keep moisture and high heat away from silver items.
That means no showering with silver jewelry on, no doing dishes, washing hands, or cooking with a ring or your finger, and definitely not going to pools and hot springs without taking out silver jewelry beforehand.
2. Be aware of what you’re touching your silver items with
Newspaper, latex, rubbers, bleach, plastic bags, cardboards; these all material can accelerate the tarnishing process. So, never store your silver in direct contact with newspapers, cardboard, and plastic bags.
3. Store your silver properly
Store your silver ornaments in drawers or boxes lined with anti-tarnish or flannel cloth. You can also wrap individual pieces using acid-free tissue or silver cloth and store them in a zip-lock bag.
4. Clean your silver once in a while
Clean your silver with warm soapy water or dip them on a hot baking soda-vinegar bath lined with aluminum foil for that extra sparkle. You’ll get rid of skin oils, food residues, and dust during the process, and the baking soda bath also removes tarnish if your pieces have any. Great, isn’t it?
How to Clean Tarnished Silver?
Cleaning tarnished silver, though quite labor-intensive, can be pretty rewarding. Your silver will come out shining and sparkly like no tarnish layer was ever formed on it. Yes, you can request professionals to do the work.
But why pay someone else to clean your tarnished silver when you can do absolutely it on your own! Here are three ways to clean tarnished silver.
1. Aluminum, baking soda, and salt
Let’s get science-y, shall we? This method might be the most favorite for many who are trying to get rid of their silver tarnish at home. In this electrochemical process, an aluminum foil plate containing your silver pieces is submerged in a hot solution of baking soda.
The hydrogen gas produced during the reaction reacts with the tarnish and reduces it back to silver metal. If the tarnish isn’t completely removed in one go, you can try this process 2-3 times. If some of the tarnish still remains, give a finishing touch to your silver process by using a polish cloth.
2. Lemon juice and salt
Squeeze some lemon juice into a container, enough to fully dip your silver item in. Let it soak overnight.
Then, take out your silver and look for areas that are still tarnished. If you see any, take some salt in a toothbrush and brush the surface. The slight abrasion will probably get rid of all the tarnish. Once you’re done, wash with cold water and dry the piece properly.
3. Silver polishes or polishing cloth
This might be a bit expensive option compared to the above two. But if you have plenty of silver to remove tarnish from, this might be your way to go.
Polishing clothes are best if you have lightly tarnished silver. Though they are impregnated with abrasive material, they are not quite as abrasive as silver polishes. So, if your silver is heavily tarshined, opt for polishes instead.
Silver tarnishing is a natural chemical process, and you can never get away with tucking your pieces for long, even if you do it safely.
With all the information in this post, you’ve got nothing to worry about. You even know how to remove the tarnish! So, what are you waiting for? Flaunt your silver jewelry without any hesitation!
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Friday 24th of February 2023
Reading your article helped me a lot and I agree with you. But I still have some doubts, can you clarify for me? I'll keep an eye out for your answers.