Rhodium plating vs. Gold plating
Why is there a price difference? How do the different colours come about?
Most Sterling Silver Jewellery on the market is white rhodium plated. Precious metals such as silver, gold and platinum are coated using a bath-plating solution made with a fine powdered form of the mineral. Black rhodium plating is exceptionally hard, so it also serves for the manufacture of precision equipment. Its corrosion resistance makes rhodium plating well suited for electrical components, too. While it has multiple uses, rhodium is a very rare mineral in nature.
At Atelier Romy, we use Sterling Silver and we rhodium plate to reduce tarnishing as, over time, silver tends to oxidise with the air and turn grey, and eventually black. This process also allows us to hide colour differences of solder* lines and so on. Rhodium is a very rare and very precious metal that can cost as much as ten times more than gold! It is a member of the platinum group of metals.
Despite its benefits, rhodium is not a very ‘usable’ as a material to make jewellery, because it is stressed and brittle and very difficult to work with. Rhodium is made for plating because it acts like a shiny, bright, white and mirror-like ‘coat’. The colour is very much close to chrome, but much whiter, and the most reflective of all metals. These days, rhodium plating can be found in various colours: white, black, grey and blue. The rhodium is only a plating and therefore, it will wear off eventually, and requires re-plating. In order for our pieces to be as low maintenance as possible, we use a very strong and thick rhodium ‘coat’ but it is important to know that, as rings are especially high wear, they may need another coat in time. That is the beauty of real sterling silver jewellery, that you can re-coat / plate it in time, where as with non-precious metal and costume jewellery, you can never bring it back to life.
Keep in mind that the tarnishing process can be affected by how you look after your jewellery, how you wear it and even by your body chemistry! We will continue to write posts over time about materials and also jewellery care. Watch this space!
Hermione & Sabine.
* Solder [noun] a low-melting alloy, especially one based on lead and tin or (for higher temperatures) on brass or silver, used for joining less fusible metals.