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ulackfocus
路All gold is not created equal. Well, not after its purity is diluted. There are different alloys classified as 18K and 14K, with different properties and colors depending on the metals used in the mixture. Copper, silver, and gold all have the same basic crystal structure which makes them ideal for combining. 100% pure gold is designated 24K, so 18K is 75% pure (18 divided by 24 is .750) and 14K is 58.5% pure. The following are typical ratios followed by the resulting color achieved.
18K
75% gold + 25% silver = green
75% gold + 16% silver + 9% copper = pale yellow
75% gold + 12.5% silver + 12.5% copper = yellow
75% gold + 9% silver + 16% copper = pink/rose
75% gold + 4.5% silver + 20.5% copper = red
14K
58.5% gold + 41.5% silver = green
58.5% gold + 34% silver + 7.5% copper = green-yellow
58.5% gold + 26% silver + 15.5% copper = pale yellow
58.5% gold + 30% silver + 11.5% copper = yellow
58.5% gold + 19.5% silver + 22% copper = pink/rose
58.5% gold + 9% silver + 32.5% copper = red
The standards for gold colors per ISO 8654 1987[E] use a simple rating system. There is some leeway in what mixture certain manufacturers use however.
0N = 14K green-yellow
1N = 14K pale yellow
2N = 18K pale yellow
3N = 18K yellow (some manufactures do call this rose)
4N = 18K rose/pink (rose & pink are mostly interchangeable)
5N = 18K red
8N = 14K nickel white
(white gold has many more variables and will be discussed in another post)
Even though the same color designation is used, different purities can yield slight changes in the shades. For example, here are two yellow gold watches from the late 50's in nearly identical condition: on the left is an 18K case and on the right is a 14K case. Manufacturers choose their alloy combinations and not all used the same formulas.
Some other metals can be substituted for 1 - 2% of the silver to change the finished product's characteristics. Zinc is the most common additive and will increase gold's fluidity while in a molten state. This facilitates easier cast molding. The addition of nickel will increase strength. Iridium and/or cobalt will refine the grain. Rolex's patented Everose uses platinum to enhance the appearance and resist tarnishing.
18K
75% gold + 25% silver = green
75% gold + 16% silver + 9% copper = pale yellow
75% gold + 12.5% silver + 12.5% copper = yellow
75% gold + 9% silver + 16% copper = pink/rose
75% gold + 4.5% silver + 20.5% copper = red
14K
58.5% gold + 41.5% silver = green
58.5% gold + 34% silver + 7.5% copper = green-yellow
58.5% gold + 26% silver + 15.5% copper = pale yellow
58.5% gold + 30% silver + 11.5% copper = yellow
58.5% gold + 19.5% silver + 22% copper = pink/rose
58.5% gold + 9% silver + 32.5% copper = red
The standards for gold colors per ISO 8654 1987[E] use a simple rating system. There is some leeway in what mixture certain manufacturers use however.
0N = 14K green-yellow
1N = 14K pale yellow
2N = 18K pale yellow
3N = 18K yellow (some manufactures do call this rose)
4N = 18K rose/pink (rose & pink are mostly interchangeable)
5N = 18K red
8N = 14K nickel white
(white gold has many more variables and will be discussed in another post)
Even though the same color designation is used, different purities can yield slight changes in the shades. For example, here are two yellow gold watches from the late 50's in nearly identical condition: on the left is an 18K case and on the right is a 14K case. Manufacturers choose their alloy combinations and not all used the same formulas.
Some other metals can be substituted for 1 - 2% of the silver to change the finished product's characteristics. Zinc is the most common additive and will increase gold's fluidity while in a molten state. This facilitates easier cast molding. The addition of nickel will increase strength. Iridium and/or cobalt will refine the grain. Rolex's patented Everose uses platinum to enhance the appearance and resist tarnishing.
