Silver characteristics

The symbol for silver, "Ag," comes from the Latin word "argentum," meaning "white brilliance." As its name suggests, silver, along with mercury, has the highest reflectivity of all metals for visible light (90% reflectivity and 98% for infrared light), and is characterized by a soft white luster. Polishing can produce a shine even stronger than platinum. Silver is also very soft, with a melting point of 960.5°C, so it is often mixed with other metals to enhance its hardness. Sterling silver, which is 92.5% silver and 7.5% alloys (used to increase product strength) (primarily copper, but also aluminum), offers sufficient hardness and is said to be the least susceptible to sulfidation, a common cause of discoloration.

Because silver is atomically unstable, it is susceptible to chemical changes, such as sulfurization, chlorination, and oxidation, which can cause tarnish. While tarnished silver is often described as "oxidized," in reality, silver does not oxidize under normal conditions unless heated to high temperatures. Most tarnish in silver is caused by sulfurization. Sulfuration refers to the process of combining with sulfur. The only drawback of silver is that it combines with hydrogen sulfide in the air to form a silver sulfide film on its surface. As this film thickens, it changes color from yellow to brown to black, causing tarnish. Additionally, sulfur compounds added to rubber bands and other rubber products (including synthetic rubber) react with moisture in the air to form sulfide gas, which tarnishes the silver. Sulfur is also found in a variety of other products, including cosmetics, shampoos, and dishwashing detergents.

If silver has become discolored due to sulfide or other factors, you can polish it with a silver-specific cloth containing fine abrasive particles, a polishing cream, or a special silver soaking cleaner to remove the silver sulfide film and restore its original shine. Sulfide can also be prevented by plating with a process called rhodium plating. For this reason, many mass-produced silver products currently on the market are plated as part of the manufacturing process, but this has the disadvantage of losing the soft, silvery texture that is unique to silver.

Brass is an alloy of copper and zinc. It is also called yellow brass because of its gold-like color. The most common brass is 65% copper and 35% zinc, and depending on the ratio of copper to zinc, it is called various names, such as red brass (5-20% zinc, also known as gold brass when it has a strong reddish color), 73 yellow brass (30% zinc, also known as yellow brass), and 64 yellow brass (40% zinc, a yellow close to golden). The color becomes lighter as the zinc content increases, and tends to become reddish as the zinc content decreases.

Brass is rust-resistant and easy to cast and process, so it has been widely used since ancient times for buildings, ships, furniture, machinery, equipment, and everyday items. It also has a soft, warm texture and an elegant luster, giving it a long history as a material for fine arts and crafts. Brass products gradually oxidize on their surface in the atmosphere, forming a film called copper oxide. This creates a unique character, and the more you use it, the more the brass's inherent beauty will increase.

If you are concerned about the darkening caused by oxidation, you can easily restore it by using commercially available polishing agents or polishing cloths. However, since natural oxidation is what gives brass its unique antique look, unless it is particularly bothersome, gently wiping off any dirt on the surface with a soft, dry cloth will be sufficient.