Why Gold Never Tarnishes but Silver Turns Black

Dig up a gold coin after a thousand years and it still shines. Leave silver in a drawer and it goes black in months.

Both are precious metals. So why does one stay flawless forever while the other slowly turns dark?

Tarnish is a chemical reaction. Most metals are desperate to bond with oxygen or sulfur in the air, building a dull film on the surface. Silver is fairly reactive. It barely touches oxygen, but it loves sulfur, and the air carries tiny traces of sulfur compounds. Silver grabs them and forms silver sulfide, a black coating that creeps across the surface. Gold is different. It sits among the noble metals, the least reactive elements on Earth. Gold simply refuses to bond with oxygen or sulfur at normal temperatures, so no film ever forms.

That's why your gold jewelry isn't really being protected. Nothing is protecting it. It's just so chemically lazy that, after thousands of years, it does absolutely nothing at all.

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