If you suddenly notice that your new gold ring appears to be leaving a black mark around your finger — don’t worry, it’s not the beginning of a zombie apocalypse! This is actually a somewhat common issue, and there are various ways to address it.

Purchasing a new piece of fine jewelry is a big decision! So once you fall in love with your new ring, if one day you suddenly notice it is discoloring your finger, you may immediately jump to some stomach-turning questions: Is my ring actually real gold? Was it cast poorly or with bad alloys?

However, the phenomenon of gold discoloring skin, clothing, or the jewelry itself is actually a somewhat common occurrence.

To understand why gold can discolor skin, let’s first review what type of gold is used in fine jewelry. Gold is measured in “karats” (different from a “carat” which is the unit of weight used for gemstones), with 24 karat gold representing gold comprised of 24 out of 24 parts gold, or pure gold. Lower karat gold, such as the 18 karat (75% gold) and 14 karat (58% gold) gold alloys most often used for fine jewelry are gold mixed with other metals like copper, zinc, nickel and silver, which makes them harder and more durable, hence their popularity for jewelry worn often.

Therefore, your gold ring probably contains many types of metal. And the most common reason for gold discoloring skin is metallic abrasion — when compounds from cosmetics (which can actually be harder than metal) rub off tiny particles of metals in the gold alloy. Very small metal particles appear black (not metallic), like a jet-black dust. When this dust comes into contact with skin or clothing it creates a black smudge. One simple solution is to switch your hand lotion! You can also remove your jewelry when doing your facial routine or putting on makeup, or clean skin areas in contact with your jewelry with soap and water.

Another cause can be the corrosion of non-gold alloy metals (gold itself does not corrode) due to exposure to extreme humidity or moisture (as well as chlorides or smog). The silver or copper in your 14k or 18k gold jewelry for example can corrode, forming blackish chemical compounds, if you wear them places like to the spa or in the ocean. Fats and fatty acids from sweat can also cause corrosion. Corrosion is therefore more often an issue in more humid and tropical areas, or if you wear your gold ring to places like the spa or swimming pool. To prevent this, take off your jewelry often if you live in or are visiting a particularly humid climate, and don’t wear your jewelry in the sauna or hot tub.

Some women have found that their rings have started to discolor skin after years of wear with no issues. In these cases (unless they’ve just switched their lotion) there is often an underlying chemical change in their body like a strict new diet, a mineral deficiency, or pregnancy!

The design of jewelry can also help or hurt this phenomenon. For example, wide shanks (the ring’s band) have more surface area to contact abrasives or corrosives, while concave surfaces inside a shank can form collection points that trap moisture.

If you are experiencing skin discoloration from your gold jewelry, you can also consider switching to platinum, to eliminate the issue entirely, or a high karat gold (such as 18k instead of 14k gold) for future purchases, which can make skin discoloration issues much less likely.

One related note, two 14k gold rings, for example, may have slightly different compositions of their non-gold alloy metals even though they are both 14 karat gold. So, it is certainly possible to wear one 14k gold ring with no issues for years, and then purchase another 14k gold ring somewhere else and have it produce some black smudging. Luckily, if this ever happens to you, you now know why and how to address the issue!