QuestionSome of my silver pieces (rings, coins, etc.) with a blue-black color (oxidation) were being kept with other various metal items. Where the unknown metal touched the silver item it built up a paste like substance and when wiped off the dull gray silver shows. Can you tell me which metal is causing this reaction and does it damage my silver item?
TIA,
Gary
AnswerHello Gary,
Sounds like a zinc chloride reaction to me.This could be from a half-baked jewelry repair using a radio shack type solder.The low melt solders are not for silver jewelry and often are overheated or break down when in contact with nickel in white gold or an alloy in a silver plated piece is reacting with an aluminum coin or piece of metal- even the container the jewelry is stored in could cause an electrolytic reaction if you are in a humid environment.
It is hard to say without looking at the environment,the pieces and their construction/fabrication, and the stones in the jewelry.Sometimes minerals are cabochon cut or left natural and unpolished or just slightly polished and can cause reactions themselves - for instance i had a client that had some zinc chloride build up on a ring that a friend of his had made then fixed.The friend set raw vanadium into the ring and it caused a reaction with the"JB Weld " he used to join the bezel to a backing plate of silver!
Alternatively flux residue , or pickle or some other fabrication or finishing related chemical is left on a piece of jewelry and not neutralized after soldering, Particularly in southwestern turquoise pieces, or central american " jades" that are leveled with sawdust to stabilize a stone in a setting. The sawdust absorbs the pickle, or the oxidizer ( liver of sulfur most commonly) and the chemicals are slowly released into the closed jewelry box as the sawdust dries out the sulfur compounds wreak all kinds of havoc on the jewelry and that could react with a cheap solder, or rather a low melt solder not intended for precious metal jewelry but more suited for electronics applications.
So it is hard to narrow it down without seeing it but It sounds like a zinc substance and probably from a reaction with an inappropriate solder and traces of jeweler's chemicals left in or on a piece.
Sorry I can't be less speculative but that is the limitation of not having a shop you can walk into in simultaneous locations around the globe coincidental to the visitors to this site's questions...try neutralizing your silver in a solution of baking soda and distilled water, for a few minutes and then drying in a hot closed car with the windows up on a sunny day, If that stops the process re-polish with a good polishing cloth (Sunshine , Selvyt or Moonshine brands are all reasonable products that are quite effective) or some jewelers rouge or precious metals compound ( available at home stores and hardware stores or jewelers suppliers on line or perhaps in your area ) on a felt bob or wheel mounted on a 3/8ths to 1/8" mandrel in a Dremel tool or other rotary tool to put the high shine back on them and then store away in 3m * anti-tarnish bags or with tissue that is acid free and wrapping each piece separately. You can get the 3M anti-tarnish strips to put into a jewelry box on line or try writing 3M's creative arts division for a sample.Also anti-tarnish felt pouches are available from a number of suppliers on line.
Main thing is to try to neutralize and stop any further reaction and then re-polish the jewelry to the state in which you expect it to remain, then store away after use.Before storing it away if you have been in a pool, jacuzzi or use colognes, aftershave etc. you may want to occasionally polish with a good cleaner and polish like Simichrome, Maas or Flitz brand following the directions then dry and store to retain the finish once you have corrected it.If all else fails write again and I can go through some other products and processes you can try if you let me know a bit more information, like what tools are at your disposal, do you live near an industrial area and/or high humidity and what stones are in the pieces that are affected...I think that we can figure out a way to arrest further disintegration if the above doesn't work.
Best regards,Ari
*And by the way,No I don't work for 3M or any of the brands I mentioned- I just use and rely on many 3M products as a goldsmith and sell them to my own customers as they outperform most everything else on the market!
