You may be wondering how we can tell where the silver is from. Most pieces of silver have marks stamped on them, called hallmarks and maker’s marks. Hallmarks typically feature several stamps that indicate the purity of the metal, where the piece was made, and the year it was made. Maker’s marks, as suggested by the name, are the marks the craftsperson put on the piece to indicate it is their work—similar to how artists sign their paintings.
While a majority of objects in this case are crafted of silver, some include unique features made from other metals and materials. These salt cellars are enhanced with a layer of gold on the interior.
In one particular case, a candlestick from this cabinet in the Dutch Room was polished to remove tarnish, and research during that cleaning revealed that the provenance attribution was incorrect. Initially thought to be Venetian, our Conservation team discovered during cleaning that the maker’s mark actually indicated that the candlestick was from the Italian city of Genoa, which is about 250 miles away on the other side of the country!
As we consider this discovery about the tarnished candlestick, and the things tarnish can hide beneath its surface, it is worth answering a key question about silver: why does it tarnish and turn black? Tarnish is a thin layer of corrosion caused by sulfur-containing gases in the air that react with the silver. The most common sulfur-containing gas is hydrogen sulfide, which many things emit—from coal-based fuel to hard-boiled eggs! In a museum setting, tarnish can take years to form, but in your own home, it could develop much more quickly.
When it comes to removing tarnish on objects in the Museum’s collection, there are several options. Our favorite method is to polish silver with a paste we make ourselves by mixing a synthetically prepared calcium carbonate that is purer and more uniform than natural calcium carbonate with deionized water. We work in small areas with a cotton swab dipped in this paste to gradually remove the tarnish and bring back the shine. Calcium carbonate is a gentle abrasive compared to many commercial polishing products, which are often much harsher and leave scratch patterns on the surface. Once the silver is polished, thoroughly rinsed, and dried, we apply a protective lacquer coating to prevent further tarnishing and the need for frequent polishing. Every time a piece gets polished, a tiny amount of silver is removed in the process—therefore, this protective coating helps us avoid polishing more than we have to!
Austrian, Pair of Salt Cellars, 1810–1824, before and after treatment