Why Does Your Silver Bracelet Turn Your Finger Green or Black? The Chemistry of Sterling Silver, Sweat, and Skin

By Dmitry Strugovshchikov, founder of STRUGA

Sterling silver is 92.5% silver and 7.5% copper, and that copper causes both things people notice.

Copper meets sulfur and builds a black film of silver sulfide that seals the surface and then stops.

Copper meets the salt in sweat and leaves green copper salts on skin, which rinse off.

Neither is damage and neither is an allergy — a darkening bracelet is usually evidence the silver is real.

Updated August 28, 2026

In the catalogue, unplated and arriving bright: Blade Mini Links V.2 — 17 g · Big Thorn Bracelet — 45 g · Thorn Bracelet — 5 g

Related reading: Men's vs Women's Silver Bracelet — Width, Length, Weight, and Why "Unisex" Is Primarily a Marketing Word.

The black on a silver bracelet is not corrosion. Silver sulfide is a self-limiting layer: it forms on the outermost surface, seals it, and stops — which is why a bracelet worn ten years is no thinner than one worn a year. Two questions reach the workshop more often than any others, usually a month after someone buys their first silver piece. Why is it going black, and why is the wrist under it faintly green. The internet answers both with the same guess — that the piece must be plated. That guess is almost always wrong.

Why does a sterling silver bracelet turn black?

Sterling silver is 92.5% silver and 7.5% other metal, and in almost all jewellery that other metal is copper. The proportion is not decorative. Fine silver at 999 measures roughly 25–30 HV on the Vickers scale — soft enough to deform in the hand; adding copper takes sterling to about 70–90 HV, which is what lets a link edge and a clasp hold their shape.

Copper is also the reactive part, and the sulfur it reacts with arrives from three ordinary directions.

• The air. Trace hydrogen sulfide, heavier near coasts, hot springs and industry.
• Your skin. Sweat carries sulfur compounds, and how much depends on what you eat.
• What you put on. Perfume, some shampoos, household cleaners — even the smell of a cut onion.

The surface then moves through a readable sequence: straw, bronze, a violet cast, graphite, near-black. What sits there is mostly silver sulfide with a smaller share of copper sulfide, and it occupies the outermost layer only. A polishing cloth lifts a young film in about two minutes.

What does each shade on the silver mean?

Tarnish is readable. The colour tells you how far the reaction has run and whether polishing is the right response at all.

What you see	What it is	What to do
Straw to bronze film	Early silver sulfide	Polishing cloth, about two minutes
Violet, then graphite	The film thickening evenly	Polishing cloth, or a silver bath if it resists
Near-black, even all over	Mature silver sulfide, sealed and stable	Polish it back, or leave it — both are valid
Green stripe on skin	Copper salts, soluble in water	Wipe the skin; lacquer the inner band if it bothers you
Pinkish dark spots	Localised copper sulfide	Polish, and check where perfume lands
Dark recesses with bright high points	Oxidation applied on purpose	Leave it alone; do not polish it out

Why does my wrist turn green under a silver bracelet?

The same 7.5% of copper causes the green, through a different reaction. Sweat carries salt, and copper meeting chloride produces copper salts that dissolve in water. They transfer onto skin and rinse away in the shower. A finger under a silver ring goes green by exactly the same route, and often sooner, because a ring sits tighter and hands are washed and creamed all day.

The comparison people reach for is the Statue of Liberty, and it is worth being precise. X-ray diffraction of that patina found it is mainly brochantite — a basic copper sulfate — with copper hydroxy chlorides only in rain-sheltered areas. Same metal, same colour, different compound from the one on your wrist.

A green mark is not the metal poisoning you, and it is not an allergic reaction. True silver allergy is very rare; nickel allergy is far more common, and sterling made properly is silver and copper with no nickel at all.

Why does my bracelet darken faster than someone else's?

Two people can buy the same bracelet on the same day and see different results within a month. The alloy is identical. What differs is the skin it sits on and the air around it.

Body chemistry

Sweat is not one fluid. It varies in pH, in salt concentration, in sulfur content. Someone eating a lot of high-sulfur food — eggs, garlic, cruciferous vegetables — puts more sulfur through the skin, and the film arrives sooner. Slightly acidic skin reacts faster with both metals. One wrist often runs ahead of the other: a difference in sweat volume, not anything unusual.

Climate

Humid, coastal and volcanic air carries more trace hydrogen sulfide. A bracelet that needs three months in a dry northern winter does the same work in three weeks near the sea. Storage follows the rule: silver in a closed box with a cotton liner stays bright far longer than silver left on a dresser.

What speeds up tarnishing the most?

None of the accelerators below damages sterling silver permanently — each simply compresses months of ordinary change into days.

What you do	What it does to the metal	What to do instead
Chlorine pool or hot tub	Attacks silver and copper together; one day outruns three months	Take the bracelet off before the water
Swimming in the sea	Salt accelerates the copper reaction, more gently than chlorine	Rinse in fresh water and dry
Perfume sprayed over the bracelet	Alcohols and oils strip the polish and speed the sulfide	Scent the skin first, let it dry, then put the piece on
Hand sanitiser and bleach cleaners	Aggressive oxidisers that work in seconds	Remove the bracelet before cleaning
Sleeping in it on humid nights	Eight hours of contact between damp skin and metal	Alternate wrists, or take it off overnight

Does a green or black mark mean the bracelet is fake?

It usually means the opposite. Darkening requires real copper doing real chemistry, fine silver hardly tarnishes at all, and a band that goes evenly dark and polishes back to bright is behaving exactly as sterling should.

So the honest test is behaviour over time, not colour.

Signal	Genuine sterling	Plated or base metal
How it darkens	Evenly across the whole surface	In patches, often at the edges first
Whether it reverses	Polishes back to bright in minutes	Wears through to a different colour underneath
The mark on skin	Green, water-soluble, gone after a shower	Grey or black stain that a cloth will not lift
The surface itself	Faint tool marks, slight asymmetry, a visible solder line	Machine-perfect, with no trace of a hand

Does the «925» stamp prove the silver is real?

No, and this is where most buying advice goes wrong. The number is older than the laws around it: the sterling standard comes from the English pound of silver struck into 240 pennies, which is why the currency is called pound sterling. The mark declares a ratio. It is not a state assay hallmark, and alone it proves nothing.

Under the United States National Stamping Act a quality mark is not required at all. When a maker does apply one, it must be accompanied on the same article by a registered trademark naming whoever answers for its accuracy — a quality mark standing alone leaves the article misbranded. Russia runs the other way round: state assay marking of domestic silver is voluntary, while the maker's mark is mandatory by law.

• An unstamped piece is not evidence of a fake. In both systems above, the absence of a quality mark is legal and common.
• A stamped piece is not evidence of anything on its own. The number is a claim by whoever struck it, not a verdict by anyone else.
• The maker is what settles it. A registered trademark, or a maker's mark, names someone who answers for the alloy — that is the part with weight behind it.

Is the dark film damage, or can it be part of the design?

Both exist, and the difference is intent rather than chemistry. The distinction decides whether you clean.

• Tarnish arrives unevenly over time, on the wearer. Living Silver is built for it: the piece comes bright, darkens where you live in it, and polishing it back is a normal part of owning it.
• Applied oxidation is built at the bench, in a controlled bath, then polished back on the raised surfaces so light catches them and locked in as a finish. It is already where it was meant to be, and cleaning takes the design off.

Worth knowing before buying: every one of the fourteen bracelets in the STRUGA catalogue arrives bright. The applied finish lives on other forms — the Brutalism V.3 Dark Treatment ear cuff among them, darkened at the bench rather than on the wearer. The split runs through the whole catalogue: every pre-blackened piece belongs to the RITUAL world, while the bracelets sit in CODEX and arrive bright. A bracelet from us is the second kind: it will darken, and that is the intended behaviour of the metal.

How do I clean a silver bracelet without ruining it?

A soft jeweller's cloth, once a week, two minutes, takes a film off before it settles. The deeper methods are where pieces get damaged, so five habits are worth unlearning.

1. Perfume after the bracelet is on. The mist lands on metal and skin together, concentrating in one spot.
2. Sleeping in it through summer. Eight hours of warm damp contact is the hardest condition the metal meets.
3. Storing it in the bathroom. That air is sulfur-rich from toiletries and drains; a dry bedroom drawer is better.
4. Cleaning with toothpaste. The abrasives cut microscopic grooves, tarnish then forms inside them, and the next clean is harder.
5. Soaking in silver dip overnight. Dip works in about thirty seconds; hours in it strip the surface and can pit the metal.

The foil-and-baking-soda method does work, pulling sulfur off electrolytically — but it strips applied oxidation as fast as tarnish, so keep it for plain polished pieces. The full sequence is in our jeweller's guide to cleaning a silver bracelet.

Which bracelet should I choose if my skin reacts?

If you live somewhere humid, swim often, or your sweat is unusually reactive, the object matters more than the care routine. Three approaches work, in rising order of effort.

• Wipe the inner band and the wrist each evening. Copper salts dissolve in water, so a cotton cloth takes them off before they mark.
• Lacquer the inside of the band. A thin coat of jeweller's lacquer puts a barrier between copper and skin, and needs redoing every few months.
• Take a rigid form instead of a close-wrapping chain. A rigid piece holds its own shape and traps less sweat against the inner wrist — the Big Thorn Bracelet carries its 45 grams off the wrist rather than around it.

Weight is the other lever. Across the bracelet range the pieces run from 2 to 95 grams, and a heavier link shows a given film later because there is more surface between the eye and the shadow. The Blade Mini Links V.2 bracelet at 17 grams sits at the median: each link is cut in half and rebuilt on copper pins, the silver carries no plating, and friction keeps the flat planes bright while the recesses collect the shadow.

The workshop cleans and makes minor repairs to any piece free for as long as it is with its owner; shipping it to us is the owner's side of that. A bracelet that records where it has been is doing the one thing this metal was always going to do.