Why Do Silver Coins Tarnish?

Silver is one of the world’s most treasured precious metals, with the first evidence of silver mining dating back to 3000 B.C. This precious and aesthetically pleasing metal is not only used as a store of value, but is also widely used in jewellery, tableware and technology. But for all its uses and beauty, silver can tarnish, sometimes to the frustration of collectors and investors.

In this article, we will explore the cause of silver tarnish, how to protect your silver from tarnishing, and whether it can affect the value of your silver coins and bars.

What is tarnish?

Tarnish, also known as ‘toning’, is the thin layer of natural discolouration and corrosion that forms on the surface of a silver item over time. Unlike rust, tarnishing is purely superficial and affects only the top few layers of the metal, often protecting the layers underneath.

Toning colours

There is a number of different colours of tarnish/toning that can appear on coins.

Black – Unearthed ancient silver coins are often black caused by the sulphides formed by organic matter in the earth.

Green – Silver coins can turn green if they are alloyed with copper, the green colour resulting from copper carbonate or copper chloride.

Yellow – Early toning on silver coins is yellow.

Rainbow - The yellow colour can progress to magenta to cyan to black. This results from the refracting of different wavelengths of light through the film, and resembles the rainbow effect that appears when a layer of oil lays on top of water.

Why does silver tarnish?

Silver tarnishes due to a chemical reaction that naturally occurs when the silver is exposed to moisture and chemicals in the air. When the atoms of silver come into contact with oxygen, a film of silver sulphide forms on the coin surface, with the underlying layers not being affected. Items made of silver will usually tarnish quickly in places where there is high humidity or air pollution.

How do I keep my silver coins and bars from tarnishing?

As humidity accelerates the rate of tarnishing, the best way to protect your silver bullion is to store your silver bullion in a container that limits its exposure to the air and the elements. Many specially designed capsules and tubes are also available in which to help protect your silver coins and bars.

It’s also helpful to avoid using your bare hands to pick up your silver bullion. Using white cotton gloves stops the oils from your fingers from being deposited on the surface of your precious metals.

The more pure the alloy, the less susceptible it is to tarnish. Silver of 999.0 fineness does not easily tarnish, so investment coins and bars are less likely to tarnish when stored safely, but may still discolour slightly over time.

How can I remove tarnish from my silver bullion?

Most collectors would recommend that you should not clean your silver coins, and it is safer to leave the tarnish as traditional silver cleaners are often abrasive. In fact, many coin collectors prefer a coin which features its original patina as it can sometimes enhance the appearance of the coin. Coins can very easily be ruined by careless cleaning, and toning is known to actually help to prevent further toning.

Some collectors and investors choose to correct dark tarnishing by using ‘dip’. This is a solvent that removes a very thin layer from the surface of the silver item. Many in the industry consider this the only acceptable method of cleaning a coin, as long as it is done properly (by a professional). However, it is often best to avoid cleaning silver coins altogether, if possible.

Does tarnish affect the value of silver bullion?

The value of silver bullion coins and bars should not be affected by tarnishing. This is because silver bullion products are typically valued by weight and purity, not specifically by condition and aesthetic appeal.

In the case of numismatic coin items, most collectors prefer coins to be in a natural state and would expect an older silver coin to have some natural toning. Patina and toning can be subjective, and in some instances, this can even increase the price of a coin.

Atkinsons Bullion and Coins have a wide selection of silver coins and bars for investment purposes. If you have any questions or would like to know more about buying or selling silver bullion, please call and speak to a member of our knowledgeable team on 0121 355 0620 or email us at info@atkinsonsbullion.com.

This blog represents one person’s opinion only. Customers should conduct their own research and take advice before making an investment. We do not offer investment advice.