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topic 9403

Test to determine if band is white gold or yellow gold plated with rhodium

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Ed. note; This is an interesting but long thread, and only one of many. Before you get too confused, you might want to start with our FAQ on Rhodium Plating and White Gold to get an overall understanding :-)

 (2001)

I read all of the postings and am now quite concerned about the wedding band I recently purchased. Does anyone know of a way to test if the ring is really white-gold or yellow gold just plated with rhodium.

Michael Krassos
- Miami, Florida


(2001)

Why not just ask the jeweler from whom you purchased the ring? The gold content of a 14K gold ring is exactly the same regardless of color, white or yellow, so there is no economic reason to rhodium plate yellow gold. If you are still suspicious you can use emery paper to sand away rhodium plate and see what is underneath.

Neil Bell
Red Sky Plating

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Albuquerque, New Mexico
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(2001)

Use Pen Gold Tester . Testing makes green rhodium ink, turns white solid nickel/gold surface to pure gold, and platinum/gold forms a yellow-red ink.

Andy Reiss
- NY, New York


(2004)

There is NO SUCH THING AS WHITE GOLD! It is ALL rhodium plated!

Tai Wade
- Los Angeles, California


Electronic Gold Tester

(2004)

Sorry, Tai. But you are in error. Although it is very common these days to rhodium plate white gold to make it blingier and whiter, white gold is an alloy of gold and nickel or gold and palladium that is definitely white, The article "White Gold Alloys: Colour Measurement and Grading" at www.goldbulletin.org/downloads/Henderson_2_38.pdf is a bit detailed and heavy, but it clearly explains everything anyone would want to know about white gold color and the ASTM D1925 color standard which is applied to rate the color.

As the rhodium wears thin on a white gold piece that is of a good color, it is just barely noticeable; but as the rhodium wears off of a yellowish gold piece it is very obvious because of the stark contrast. That is why it was never considered acceptable to rhodium plate yellow gold, although it seems that some jewelers are doing it today instead of stocking the pattern in both white and yellow.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


(2004)

Hi Michael

I have two methods for you to try

Both use the specific gravity test to determine the gold content of your ring, one is a formula, the other is a chart.

Method 1

Step:

1) Weigh your ring eg: 10.00 grams

2) Place a beaker half filled with water on a scale. The scale will have to be re-zeroed with the beaker & water on it. If it does not have this feature try turning the scale off then on with the beaker & water on it. See your local butcher if you can't get hold of a scale.

3) Attach a fine thread or hair to the ring and submerse it in the water. NB it must be fully submerged but suspended "not touching the sides or bottom". Take the reading off the scale eg: 0.56 grams

4) Divide the dry weight of the gold by the suspended one eg: 10.00 \ 0.56 = 17.8

5) Multiply the result by 5.096 eg: 17.8 x 5.096 = 90.7088 percent gold.

Method 2: using the result from step 4 match it to the row titled weight. The value adjacent will be the percentage of gold present.

eg 17.8 92% "close enough to the previous test!"

Weight		%
11.37		45
11.53		47.5
11.64		50
11.8		51
11.91		52
12.02		53
12.12		54
12.42		57
12.52		58
12.6		59
12.69		60
12.8		61
12.93		62
13.06		63
13.19		64
13.31		65
13.46		66
13.61		67
13.77		68
13.92		69
14.07		70
14.22		71
14.39		72
14.52		73
14.68		74
14.83		75
15.06		76
15.29		77
15.53		78
15.76		79
16		80
16.15		81
16.3		82
14.45		83
16.6		84
16.75		85
16.9		86
17.05		87
17.2		88
17.35		89
17.5		90
17.65		91
17.8		92
17.95		93
18.1		94
18.25		95
18.46		96
18.67		97
18.89		98
19.1		99
19.3		100
 

Regards
Scott

Scott, Alexander
- Harare, Zimbabwe


April 13, 2009

Does the specific gravity test only work on purely gold rings? For example, this test would be flawed if testing a ring with a diamond on it, correct?

H.D. Jennifer
- Utica, Michigan


September 5, 2010

I would think so, you can factor out the estimated weight of the stone.

Cathleen McCoy
- Hilton Head Island, SC, United States

September 25, 2010

So under this method, if it ends up with say 90% purity then does that mean it is indeed plated.
If it is 100% then it's pure white gold?
Thanks.

Tyler Hendricks
- Federal Way, Washington, USA

February 24, 2012

There is no such thing as pure white gold.

Shawn Hansen
- Fresno, California, USA


February 27, 2012

Exactly. Gold is an element and it is always yellow. So 24 kt gold (24 parts out of 24) is always yellow. Jewelry is usually a mix of gold and other metals, though, so 10K (10 parts out of 24), 12K (12 parts out of 24), etc., can be white depending on what those other metals are.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



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