Jewelry turns your skin green because copper in the metal reacts with sweat, skin oils and moisture. The copper forms green salts that settle as a thin film on the skin. It is a chemical reaction between metal and skin, not a sign that something is wrong with your skin, and the green discoloration can be washed off with soap and water.

The reaction depends on both the jewelry and your own skin. The more copper a piece of jewelry contains, and the more acidic your sweat is, the faster the mark appears. That is why the same piece of jewelry can leave clear green traces on one person and none at all on another.

What is the green stuff on the skin, really?

The green color is copper salts. When copper comes into contact with oxygen, moisture and the salts and acids in sweat, the surface of the metal oxidizes. Among other things, copper carbonate and copper chloride form, both of which have a greenish color. It is the same process that over time gives old copper roofs and statues their green coating.

When the reaction happens directly against the skin, the green compounds settle as a thin layer on the surface. The layer does not embed itself in the skin and does not penetrate into the body. It is harmless and disappears when you wash the area.

If, on the other hand, you experience itching, redness or swelling, that is something different from the green discoloration. It can be a sign that the skin is reacting to a metal in the jewelry, and here nickel is the most common cause.

Why do my earrings smell, and why does my skin turn green?

Green skin and smell from earrings often have the same root: a reaction between metal, skin oil and bacteria. In a pierced ear, sebum, dead skin cells and sweat gather around the post, and this can produce a characteristic smell, regardless of which metal the earring is made of. Copper in the jewelry's alloy can additionally cause the greenish discoloration.

So the smell is mostly about cleanliness around the piercing, while the green color is about the metal. Both become stronger if the earrings are rarely taken off and rarely cleaned. A regular cleaning routine keeps both problems down - how to clean earrings goes through the procedure.

This is why copper is the real culprit

Pure copper and alloys with a lot of copper are behind the vast majority of green marks. This applies to jewelry in brass and bronze, both of which contain copper, and it applies to cheaper jewelry where copper or brass makes up the base metal itself.

Gold-plated jewelry is a special version of the same problem. Here a thin layer of gold sits on top of a core of brass or copper. As long as the layer is intact, the skin only touches the gold, but when the plating wears off, the base metal comes through, and then you are in practice wearing copper directly against the skin. This is typically the reason a gold-plated piece can look fine when new and only start to leave marks after weeks or months.

Silver itself does not cause green marks, but sterling silver is 92.5 percent silver and 7.5 percent other metals, most often copper. That small proportion can be enough to cause discoloration in some people. Longvé uses sterling silver for, among other things, signet rings and a few chains and bracelets.

Does 14K gold also react with the skin?

Pure gold does not react with the skin. It is a so-called noble metal that resists the chemical reactions that cause other metals to tarnish. The problem is never the gold itself, but the metals it is mixed with.

Pure gold is too soft for jewelry meant to be worn daily, so it is alloyed with other metals to become strong enough. In 14K gold, a little over half is pure gold, and the rest is, among other things, copper, silver and zinc. The copper is the reactive part, but in solid 14K gold it is bound stably into the alloy and does not lie exposed as a separate layer against the skin. That is why a solid 14K gold ring behaves completely differently from a gold-plated ring with a core of brass, where the copper comes through as soon as the plating is worn through.

Solid 14K gold therefore rarely leaves green marks under normal use. If it does happen anyway, your own skin plays a role: acidic sweat and a lot of moisture can bring out a faint mark even on an alloy with relatively little copper. The same applies to 14K white gold, where the gold is mixed with white metals to achieve the light color.

How do you keep a ring from rubbing off on your finger?

The safest approach is to choose a piece of jewelry where no reactive copper lies exposed against the skin. Solid 14K gold and 14K white gold are good choices, precisely because there is no base metal that can come through and rub off. Platinum and titanium do not discolor either, while gold-plated and copper-heavy jewelry are the ones that most often cause problems.

Beyond the choice of material, it helps to keep the jewelry dry and clean. Take rings off before you wash your hands, play sports or use hand cream, and dry the jewelry off if it gets wet. Residues of soap, lotion and sweat under a ring increase the reaction, because the moisture is trapped against the skin. A regular cleaning habit removes the coatings before they build up - how to clean jewelry describes how to do it gently.

If you are particularly prone to green marks, you can also store jewelry in a dry, airy place so the metal does not tarnish between uses.

Are green marks dangerous or a sign of fake gold?

A green mark is harmless in itself. It is a surface reaction between copper and skin, not an allergy, and it washes off. An allergic reaction shows up differently, namely as itching, redness or swelling, and is typically caused by nickel rather than copper.

Green skin also does not automatically mean that a piece of gold jewelry is fake. Almost all gold contains a little copper, because pure gold is too soft for jewelry, so even genuine gold can in principle leave a faint mark under the right conditions with acidic sweat and moisture. The difference is the amount of copper. A solid 14K gold piece has a small, stable proportion, while a gold-plated piece can be almost pure copper or brass under a thin plating. If a piece of jewelry rubs off constantly and heavily, it is more often a sign of precisely a gold-plated or copper-heavy construction than of the gold being false.