does gold tarnish

[pearlescence]

Does anyone have any authoritative info on whether gold (various carats) tarnishes, and if so, how?

[Dennis]

9ct yellow, red and white, certainly tarnish Wendy, due to the proportion of non precious metals in the alloys. In fact they get to look quite sad.

When this happens, I am asked to clean up my pieces, and usually a dip in Goddard's, and a brisk brush with soapy water restores them as new. Heavy tarnish require more aggressive polishing

I guess higher carats would do so more slowly, and 18ct hardly at all. Dennis.

[pearlescence]

Thanks Dennis, but that is empirical, I was hoping for academic and scientific.
Someone is insisting on another forum that what is plainly copper is tarnished gold...

[Dennis]

Well the only way to tell in that instance is with a gold testing kit. They they are not that expensive to buy.
Pure gold of course does not tarnish, as witnessed by the colour of found nuggets, and ancient buried treasure.
However here is Ganoksin on the subject, considered to be the go-to authority by jewellers:

https://www.ganoksin.com/article/gold-jewellery-tarnishing/

[ps_bond]

http://www.santafesymposium.org/2000-santa-fe-symposium-papers/2000-high-carat-golds-do-not-tarnish
But there's not much out there I've seen in the analytical realm, mostly it's hearsay.

[pearlescence]

I think I'll bide in silence then, thanks Denis and Peter

[ps_bond]

I'm sure you're aware of the adage "never argue with an idiot" :)