“Antiquing” or “oxidizing” silver is fairly common in the jewelry industry. It results in a patina finish, which darkens details and engraved areas on jewelry so that they’re more visible.
There are several methods to achieve this process, but the most common uses a solution known as Liver of Sulfur (LOS). LOS is a mixture of two chemicals, 25% potassium trisulfide and 75% hydrated potassium thiosulfate. It reacts with the copper in sterling silver and leaves a blackened coating on the surface called silver sulfide.
LOS itself is moderately toxic, mostly because of the gas it releases during use. The actual solution of LOS does not remain on the surface of the jewelry after use; part of the process of using LOS is submerging the jewelry in a neutralization bath to, well, neutralize any remaining solution. After the neutralization bath, only the resulting silver sulfides (the blackened coating) remain. Antiqued or oxidized jewelry is completely safe for skin contact.
After jewelry is antiqued or oxidized, the piece goes through extensive polishing and cleaning so that the darkened coating only remains in the engraved areas and details of a piece. The darkened silver sulfides are generally not toxic in the small traces left on your jewelry. However, we still recommend that you not put any antiqued/oxidized jewelry in your mouth, as it may cause minor stomach irritation – not to mention, it’s just weird to put your jewelry in your mouth.
You can read the msds here for ingestion of larger quantities/higher concentrations.
We’re here to answer any questions you may have about the safety of ShineOn jewelry. Email us at firstname.lastname@example.org.