What Causes 18k Gold to Tarnish? – How to Store Them?

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Although pure gold is a precious, tarnish-resistant metal that never discolored, gold alloys discolor at varying degrees, depending on how the blend is created.

In the case of 18k gold, discoloration or tarnishing takes place, but at a much lower rate than other alloys like 14k and 10k gold. Gold alloys are often made from mixing pure gold with metals like copper, silver, zinc, iron, aluminum, and even palladium.

18k gold comprises 75% pure gold and 25% other metals. Unfortunately, 25% is made of different metals that are highly reactive, and these are the reasons for the oxidation of 18k and the subsequent tarnishing.

This article shares more insights on everything you need to know about 18k and why it tarnishes. But first, the basics.


About 18K Gold

What Causes 18k Gold to Tarnish

Gold Karat is defined as the measure of the amount or percentage of precious metals in the piece of jewelry it is made of. 18k gold is considered the purest version of gold that is used to create jewelry, and 18k gold jewelry refers to jewelry in which out of the 24 parts that make up pure gold, 18 parts of that are made of gold while the remaining 6 parts are made of other metals.

In percentage terms, the 18k piece is made of 75% pure gold and 25% metal alloys like nickel, copper, and zinc. Note that alloying gold is critical for hardening the gold alloy and enhancing its strength, hence more durable gold jewelry. Overall, 18K gold jewelry is the best quality gold jewelry.

What Causes 18k Gold to Tarnish

The catch, however, is that despite the high percentage of pure gold and its alloying, it is not hard enough. It’s quite malleable, and it will bend easily. It also scratches easily.

So, if you have jewelry made of 18 gold, you should pay more attention to that jewelry and avoid knocking it around. An 18k ring, for instance, looks stunning, but you should take it off whenever you’re cooking, cleaning, showering, sleeping, or gardening.

Otherwise, your 18k jewelry will last a long time and hold value well.

What Causes 18k Gold to Tarnish

The other caveat you should be aware of is that despite the high concentration of pure gold, the 18k gold alloy will become dull because of the reaction of the alloys with different environmental factors and elements.

Over time, the dulling worsens, and the jewelry will show more signs of tarnishing and discoloration to some degree.

So, how do you recognize 18k gold jewelry pieces? First, look for its stamp of approval, the karat number stamped on the piece. The stamp on the jewelry will be in different forms, including 18K (the most common) or 18Kt.

Other versions of 18K gold jewelry are marked differently, with the three-digit number representing the percentage of gold in the gold piece, in this case, 750, to match the 75% pure gold in the jewelry.


What causes 18k gold to tarnish?

What Causes 18k Gold to Tarnish

Although 18K is the least reactive gold alloy used in jewelry making, it still tarnishes to some degree.

You may only notice that tarnishing as the jewelry looks dull and no longer as shiny as it was, but that is enough evidence that the gold jewelry tarnishes. So, it would help if you didn’t ignore the 18k pieces thinking they will not tarnish because they always tarnish.

That said, the metals added to gold to create 18k gold will determine how fast tarnishing happens. If it’s alloyed with copper, zinc, or aluminum, tarnishing will happen much sooner. It will be more significant than 18k yellow gold alloyed with silver since silver has very low reactivity.


Tips for wearing your 18k gold jewelry (To Make It Last longer)

What Causes 18k Gold to Tarnish

Your 18k gold jewelry will last a long time if you keep its tarnishing at bay and also if you get rid of all signs of oxidation early on. The best way to prevent tarnishing is by doing the following.

I. You should always remove the 18k gold jewelry before you shower or wash your hands. The soap from your hand or body wash will always leave a dull finish on your gold jewelry, making it much harder for you to clean the jewelry. Over time, the 18k gold pieces will look old, and the oxidized film will grow thicker, so you should take it off frequently, especially when around water.

II. Take the jewelry off before swimming. In addition to risking the loss of the ring or the earrings since they may fall off easily and disappear forever, you shouldn’t swim with your valuable gold jewelry because the chlorine in the pool and saltwater in the ocean will speed up the rate of tarnishing. So, just avoid salty and chlorinated water for the ring to last longer.

What Causes 18k Gold to Tarnish

III. If you have to keep your jewelry on in wet conditions, you should be more aware of the jewelry and ensure that the jewelry doesn’t stay wet for too long.

IV. Take your 18k ring off when cooking, and avoid exposing it to acidic foods like pickles, onions, lemons, and spices since all these would make the jewelry tarnish much faster.

V. Wear your jewelry after cologne, perfume, lotions, and hairsprays.

VI. Avoid contact with detergents


Tips for storing your 18k gold jewelry

What Causes 18k Gold to Tarnish

  • Invest in a nice, velvet-lined jewelry box to store your jewelry in, and make sure that the box allows you to keep the jewelry pieces separate to reduce scratches as the pieces rub against each other.
  • Keep the jewelry box airtight and away from humidity by putting silica get pack in the box. Without the silica gel pack, you could also use chalk because it absorbs moisture.
  • Always keep the jewelry safe in a jewelry box when you take the pieces off.
  • Store the jewelry in an anti-tarnishing gold pouch or an airtight plastic container, or a Ziploc bag


Even though 18k is the finest quality version of gold used in jewelry making, it is not 100% resistant to tarnishing, which is why you need to protect it from water, oils, perfumes, acidic components, chlorinated pool water, soap suds, etc.

Read more jewelry metal posts here or here

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