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Hardness of white gold vs. yellow gold

I am in the process of purchasing a white gold wedding band, and have received conflicting information from jewelers as to the hardness of white gold as karat value increases. Most have said that both white and yellow gold decrease in hardness (i.e., scratchability) as you go from 10K to 14K to 18K etc. A few however, have said that hardness of white gold is the opposite of yellow, in that 18K white gold is harder than 14K white gold. I don't understand why this would be, assuming the alloys used to make the gold white are the same in each case (eg. both 14K and 18K with nickel, or both with silver). Given the same whitening alloy, more gold content should mean a softer ring regardless shouldn't it?

Oliver Laser
Consumer - Calgary, AB, Canada
2006

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There is no isotope of gold that is white, Oliver. All pure gold is yellow, and white gold is made by alloying the gold with whitening agents. Thus if in your theoretical situation of adding the same quantities of the same alloying materials, what would account for one ring being white and one ring being yellow? I don't personally know the maximum karat of white gold, but it would seem to be difficult to make it white if 18 out of 24 parts are yellow gold. In other words, I have no answers to your questions, only more questions.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2006

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First of two simultaneous responses --

There is no way 18K gold (white or yellow) can be harder than 14k. As Ted said the closer you get to 24k gold the softer the jewelry is. Most white gold is 14K, some 10K. Depending on the whitening alloys used, white gold can be harder than yellow gold. If you get white gold make sure it is plated in rhodium for added wear resistance.

Mark Baker
process engineer - Malone, New York
2006

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Second of two simultaneous responses --

I don't have any more answers than Ted does. But, since you mentioned nickel as the alloying agent, I thought I'd point out that finishing.com gets letters on a regular basis of people who've suddenly figured out their allergic to their jewelry because of nickel and are now in the position of figuring out what to do. If you're buying the ring now, whichever one you choose, I'd try looking for one that is certified as being Nickel Free.

Good luck.

Jim Gorsich
Compton, California, USA
2006

18k white is possible 'cause I am wearing an 18k white ring. Also, I sell jewelry and we sell 18k white. It is stronger because jewelry manufacturers use 18k white gold on the clasp workings on 18k yellow bracelets.

Carole Thomas
- Greenville, North Carolina, USA
January 29, 2012

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