Creating Beautiful Dark Patina on Jewelry Pieces
Sterling silver, or pure silver, contrary to what is popularly known, does not oxidize, since, being a noble metal, it does not react with the oxygen in the air, therefore, it would not be correct to say that oxidation occurs. In reality, the dark color of silver happens when it reacts in the presence of sulfur. Oxidation, therefore, begins by turning to a yellowish color and gradually becomes quite dark.
Sulfur is a mineral present in our body, therefore, silver in contact with our skin, depending on the PH and other factors, reacts naturally and begins the process that we popularly call oxidation. Also, sulfur is found in some perfumes and soaps, and even in the place where we keep our jewelry. Because of this, without intervention, the silver will darken over time.
What we do in the Jewelry workshop, is to provoke this reaction, getting in a faster way, this oxidation. Using chemical compounds such as potassium sulfide or sulfur liver, we artificially create a dark patina on the surface of the silver piece. Since this is a process in which only the surface is blackened, to preserve the patina, it is usually protected with varnishes or waxes. Depending on the rubbing of the piece, even with this protection, this "oxidation" will change over time, revealing the true color of the silver. The wear will not be the same on earrings as on a ring, since the earrings hardly have any rubbing, while on the ring, the patina will be much less durable. In earrings, the patina will last for a long time, and even the passage of time will help its conservation, if we keep the piece separated, without being touched by other jewelry.