Costume Jewelry Ring with Rhodium Plating
I have a ring that's rhodium plated and brass underneath, but it's a matte finish ...the finish rubbed off and the ring turned my finger green...what could the makers be using to give it the matte finish?
Rhodium plate by itself cannot be given a matte finish in most cases. It is usually the texture of the underlying metal which will give rhodium plate a matte-like look.
Rhodium plate is usually applied at a width equal to 1/100th of the thickness of one strand of hair. Rhodium plates are so thin for a number of reasons:
Rhodium plate is a rare metal that is also extremely expensive – thicker plates would cost a lot more than the mico-thin plates.
If rhodium plate is applied at a thickness of 2 microns or more - which is about 2/100ths of the width of the average human air – the plate can become brittle. (Just as an aside, rhodium’s brittle nature is also a reason why pure rhodium rings are not really possible).
Because rhodium plate is so thin, any attempts to give the plate a matte finish would usually remove the layer of rhodium plate.
It is most likely the texture on the surface of the brass band which gave the ring its original matte look - but if that texture on the brass wore away than the ring probably won't look quite the same if it is plated again.
Rhodium plate too will bring out any minute details on the surface of a band – including very light scratches – so it is possible that the features on the brass which created the matte look with the rhodium plate are difficult to see….they could be very tiny details that are brought out visually by the rhodium plate.
The copper in the brass is probably what is causing your finger to turn green – but if your finger is turning green and accompanied by any symptoms like itching or irritation you could be having an allergic reaction to the light layer of nickel which is applied over metal rings before the rings are rhodium plated.
If you intend on wearing the ring again, it is best to have the rhodium plate reapplied. The ring may look like it used to, as long as the original texture on the surface of the brass band remained the same.
Or, you could have a jeweler remove the rhodium plate, rough-up the band a bit and then re-apply a rhodium plate to restore the ring’s original matte look. However, this might cost more than the original value of the ring.
Alternatively, you could also paint the inside of the ring with clear fingernail polish to protect your finger from any reaction with the copper and/or possibly nickel metals. If you do decide to place fingernail polish on the ring though, and you decide to have the ring rhodium plated down the road, be sure to tell the jeweler that the ring has fingernail polish on it as the polish will need to be completely removed before the plate is applied.
I hope this info helps, and do write again if you have any additional questions!
Suzanne GardnerEverything Wedding Rings