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Body chemistry and sterling silver


I have worn my sterling silver earrings for sometime without them tarnishing, but just the other day I put them on and they tarnished in about three days. So, I decided to put on another pair, and they turned as well.So, then I put on my third pair and they also turned. Now my question is, "Does your body chemistry have anything to do with the tarnishing of sterling silver?", because my earrings are as black as smut.

Yolanda L [last name deleted for privacy by Editor]
- Decatur, Georgia, USA


Dear Yolanda,

Changes in body chemistry can effect the tarnish rate on sterling silver jewelry. Amino Acids in the perspiration contain sulfur or sulfides and the presence of sulfur or sulfides accelerates the rate of tarnish. Changes in hormone balance during adolescence or change of life in women has been known to change the bodies chemistry. Medications or chemotherapy can also effect the body chemistry. Some cosmetics and skin lotions can also accelerate tarnishing in silver or lower karat gold jewelry. Try cleaning your silver jewelry in dish washing detergent and water after wearing it, be sure to completely dry it. This will help remove skin oils or perspiration and may help keep silver jewelry clean and bright longer.

Best regards,

Jim Sivertsen
United Precious Metal Refining Co. Inc. - Alden, N.Y.

April 14, 2008

Dear Sirs,

We currently manufacture silver plated jewellery and we have experienced a blackening effect occurring on skin and apparel when the jewellery is worn.

We use brass raw material as our base product then we plate with copper strike, a coating of palladium and then 5 microns silver followed by Palladium Cobalt Preservation PCP. Our question is what could be causing the blackening effect?

We have tested for tarnishing and there is no tarnishing occurring.

Thank you for your help and assistance in this matter.

Kind regards from Hong Kong!

John Barnes
Manufacturer of O.E.M Products - Hong Kong

April 16, 2008

Sorry, further to my previous enquiry, need to inform you of the exact plating spec we use for our jewellery, it is as follows:

Brass ( Base Material)
Copper Flash Plating: Cu 99.99% P:0.01%
Palladium Flash Plating: Pd 80% Co:20%
5 Microns Silver plating: Ag 100%
Protective Coating TPS (Passivation)

We are puzzled as to where the blackening can be occurring that stains the skin and garments black!

We are told it could be the result of an insufficiently thick protective components such as a combination of Miralloy, flash palladium and high quality plating to produce a porosity free-free plating.

Your professional view and advice would be appreciated.

Thank you very much,

John Barnes
Manufacturer of O.E.M Products - Hong Kong

April 23, 2008

Hello John,
As you probably already know, the palladium - cobalt flash coating is used as a diffusion barrier plate between the copper and silver. This flash coating may not be sufficient to hold back diffusion of the copper into the silver. When I hear skin turning black I think of copper migration. A pure silver plate alone will not turn skin black, unless the tank is full of metallic contaminants.
I would also suspect the PCP process, it doesn't seem to be holding up. There are a few steps you can take for corrective action measures.
1) Plate two sample lots; one lot with the normal flash coating of Pd-Co. The other lot plated with a higher thickness coating of Pd-Co, say a 15 microinch thickness and follow the rest of your process for each lot.
2) Have your customers evaluate each sample lot to see if the problem arises in either lot.
3) Have your Pd-Co Preservation supplier check out your process thoroughly by completing an analysis, or coating samples for you with your solution to see if there's a problem there. Have them verify that you are using the proper shipping and storage packaging as well. Hope things work out for you.

Mark Baker
process engineer - Malone, New York

April 24, 2008

Hi Mark,

Greetings from Hong Kong!

Thank you very much for your valuable advice.

Much appreciated and will try your recommended steps.


John Barnes
- Hong Kong

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