Why does gold turn black?

For thousands of years, gold has been used to create exquisite jewellery pieces, coins and other decorative objects. However, have you ever wondered why gold sometimes appears to turn black? This article will explore the reasons why gold can lose its shine, how to clean gold jewellery that’s turning black and how to prevent your gold from tarnishing.

What causes gold to turn black?

Abrasion

If we wear gold jewellery every day, the likelihood is it will come into contact with many different substances on our skin, such as hand cream, perfume, hairspray and makeup. Cosmetics, in particular, contain abrasive compounds that can rub against the metal and cause tiny particles to dislodge, which causes discolouration of the gold.

Corrosion

Corrosion is a reaction that occurs between metal and its environment, causing a breakdown of the metal's surface. While pure gold is resistant to corrosion, gold alloys that contain other metals such as silver or copper can corrode when exposed to moisture or wet conditions. This can result in the formation of dark chemical compounds that appear black in colour.

Additionally, when exposed to certain elements such as the fatty acids contained in sweat, the corrosive process can be accelerated, leading to further discolouration.

Exposure to chemicals

Exposure to chemicals found in cleaning products, cosmetics and other substances, is another reason why gold can turn black. Chlorine, for example, is a potent oxidising agent that can cause gold to tarnish and lose its shine.

Similarly, exposure to sulphur compounds found in certain foods (such as onions or eggs) can cause gold to discolour. This is why it's important to handle all gold jewellery with care and avoid exposing it to chemicals that can damage its surface.

Why does gold turn my skin black?

If your gold jewellery is turning your skin black, there are a few reasons why this might be happening. One of the most common reasons is that your jewellery is not actually pure gold. Gold is often mixed with other metals, such as copper or nickel, to make it more durable. However, these metals can react with the acids and oils in your skin, causing a chemical reaction that turns the gold black, resulting in a dark smudge on the skin.

Similarly, exposure to harsh chemicals in detergents, chlorine-treated pools, cosmetics or skincare products containing abrasive elements can cause the metal to corrode and turn black, which can also leave a mark on your skin.

How to clean gold jewellery that’s turning black

If your jewellery is turning black, there are a few steps that you can take to clean it:

1. The first step is to remove any dirt or debris from the jewellery using a soft-bristled brush.
2. Next, use a simple solution of warm water and dish soap. Soak the jewellery for 20 minutes in the solution, then gently scrub it again with a soft-bristled brush if needed.
3. Rinse well with plain water and dry with a soft cloth.
4. Alternatively, you can make a paste of baking soda and water and apply it carefully to the jewellery.
5. Rub gently to remove the blackness, then rinse and dry. Avoid using harsh chemicals or abrasives that can damage the gold.

How to stop gold from tarnishing

To prevent gold from tarnishing, avoid wearing your gold jewellery when using bleach, chlorine, cosmetics or other harsh substances. You should also remove your jewellery before swimming, showering or exercising. To keep your gold jewellery shiny and clean, you should regularly wash it with a mild soap and warm water. Keep your jewellery separated by type, as interaction with other metals can also lead to tarnishing.

Does real gold turn black?

Real gold does not turn black by itself. However, it can turn black if it is mixed with other metals that react with oxygen or other chemicals, known as tarnishing or oxidation. Pure gold is 24 carat and does not tarnish, but most gold jewellery is lower carat and contains other metals such as copper, silver or nickel. These metals can corrode and turn black over time.

Does tarnished gold depreciate its value?

Gold that has turned black can depreciate its value. The cause of this would be the composition of other metal alloys, such as nickel, copper and zinc, which are capable of tarnishing and discoloration. The change in appearance can reduce the visual appeal of any gold item, along with its value. To retain its value, make sure you clean your gold items carefully and store them in a separate jewellery box or container to other metals.

Looking to sell your unwanted gold?

If you’re looking to sell your gold and not sure where to start, why not check out the Gold selling process section of our website? As an independent postal gold buyer comparison site, we are committed to helping you find the right buyer, ensuring you get the best value for your unwanted gold.