Gold plated DOES tarnish if it contains metal alloys.
The rate at which a gold-plated object will tarnish will entirely depend upon how much of the piece contains alloys.
What Are Alloys?
Gold weighs in at 2.5 on the Moh’s scale for mineral hardness, making it one of the softest metals on Earth. Because it is extremely malleable, most gold jewelry is designed with additional alloys to make it more practical for everyday use. The addition of alloys is rated in karats, the higher the karat, fewer additional alloys have been added to the gold.
How Are Karats Measured?
Karats are measured using a formula of a proportion of 1/24. The karat weight is divided by 24 then multiplied by 100 to find the percentage of gold piece contains.
For example 24K gold would be 24/24 or nearly 100% pure. 18K would be 18/24 or about 75% gold 25% alloy. 14K gold would be 14/24 or 58.3% gold 41.7% alloy and so on.
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