Why does gold tarnish?

"Gold Plating Technology"
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A. Hi,

Gold as such will not tarnish. It is inert. The tarnish-like appearance is due to underlying surface getting corroded or oxidized. If the thickness of gold is not adequate and if the coating is porous, the corrosion taking place in the underlying surface may seem like tarnish. Ensure that you have adequate thickness build up of gold, to put an end to your problem.

Good luck ...

A. Gold does NOT tarnish. if you wish, post a detailed picture and we'll advise further.

A. Hi,

If you have nickel plating as a finish to plate gold onto it will normally not tarnish even if you only deposit 0,1 micron of gold. This could mean that the gold plating solution has contamination, which tarnished. If you have nickel-free plating and plate gold onto copper or bronze the tarnish would come from the base if the gold plating is too thin to form a uniform layer without pores.

Good luck and all the best,

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A. Hi, Minou. My understanding is that 24 karat gold will not tarnish; but jewelry is usually made of a lower karat which contains copper or nickel or silver or other metals, and a lot of gold jewelry will tarnish in chlorine. However, the tarnish layer is probably thin and a jeweler can probably restore the shine with some polishing. But don't wear gold jewelry into a swimming pool or hot tub.

Regards,

A. Gold plating has only little effect on nickel materials, but it's best on gold, silver, and copper. Heavy plating can be used.

A. Hi Roz. I'm surprised that 24 kt gold would tarnish as 24 kt gold is extremely chemical resistant. Are you sure it's 24 kt rather than a lower karat, or only plated with 24 kt?

Don't mess with further chemical treatments. Try buffing off the discoloration with a jewelry cloth and a very mild abrasive like light duty rubbing compound ⇦this on eBay or Amazon [affil links] or even tooth paste.

Regards,

A. Stacy,
Buffing might work in terms of restoring the original luster. Best wishes!

A. Hi Stacy,

If the photo of your earrings is representative of the real thing, then you have a serious problem. 18 KT gold should not tarnish like that in normal domestic or workplace environments. You can see examples all around you. Are you quite sure that the earrings are solid gold and not electroplated? I strongly suspect that the latter is the case. Thin gold electrodeposits will migrate into the underling metal giving serious tarnishing!

Trying Blake's suggestion should resolve the matter.

Harry

A. Hi Darlene. "18kt gold plated" is actually an oxymoron. 18kt means the jewelry is solid gold through-&-through of 75% (18/24) purity (the remaining 25% is copper, silver, nickel, palladium, or other metal to make the gold less soft). 18kt gold will not fade or chip; tarnish probably would not be a problem unless you wear it into a hot tub or work with chemicals.

"Gold plated" means there is a thin veneer of gold plating on the surface of the jewelry, which is made of something else (possibly brass or zinc). Some gold plated jewelry is very good quality and will last for years, but a lot isn't. Unfortunately, it's not easy to know the quality of a plated item from its description. You'll have to rely on the brand name of the jewelry or the jewelry shop.

Regards,

A. Hi Reginald. 24 kt gold, i.e., 100% pure, does not tarnish. 10 kt gold, i.e. 42% gold, 58% other metals certainly can tarnish from chemical exposure, but probably won't tarnish much unless exposed to tarnishing agents like cleaning solutions, bleach/chlorine, bromine, etc.

If you're sure your fiance did not wear the rings while doing laundry, cleaning, or swimming in a pool with chlorine there might be a problem. Otherwise, try cleaning with toothpaste or taking to a jeweler for re-polishing and simply avoid those things with the rings on in the future. Good luck.

Regards,

A. Hi Reginald
My wedding ring is 9kt. It has been on my finger for 50+years and never removed. It has been exposed to all manner of nasty chemicals and only ever cleaned in the process of normal hand washing. It has less sign of wear than the finger it is on.
If your ring is truly certified 10kt, tarnish is unlikely to be the cause of discolouraton.
Hair spray, fake tan, furniture polish, etc., are worth considering as a possible cause.

A. Hi Rachel. I'm not a jeweler and know nothing of the subject, but gold plating is generally very very thin. Attempting to etch a discernible pattern into it but not go through it, doesn't sound practical ... and brass will certainly discolor. You probably need to lacquer it if you want it to not change.

Regards,