Vitreous china is an enamel coating that is applied to ceramics, particularly porcelain, after they’ve been fired, though the name can also refer to the finished piece as a whole. The coating makes the porcelain tougher, denser, and shiner, and it is a common choice for things like toilets and sink basins. Some artists also prefer it to “regular” ceramics, and it had a number of roles in ancient civilizations, too.
How It’s Made
The word “vitreous” means “glass-like,” and that’s just what the glaze does for ordinary ceramics: it makes them look shiny and reflective while maintaining and in most cases actually strengthening their durability. The glaze itself is usually made of composite minerals and powdered glass. It is typically sold as a powder that artisans and manufacturers must melt down, in a kiln or specialized oven, before using.
Once the glaze has reached its melting point it can be painted, or “glazed,” onto the surface of the ceramic piece. Most of the time the piece getting painted must otherwise be finished, making this one of the very last steps. The enamel must usually be left to dry for a time, then the piece re-fired to seal the coating. Past this point, the item can usually be itself described as “vitreous china.”
Main Differences From Other Ceramics
Many people believe that vitreous china is its own category of ceramic products, but this isn’t usually the case. With the exception of the top glaze, these sorts of items, be they sinks, bathtubs, or other fixtures, are the same as their unglazed counterparts, at least in terms of material composition. Most manufacturers start with ordinary porcelain products that they make vitreous at a later point. The outside surfaces look different, but the underlying products tend to be identical.
The glaze gives vitreous pieces a distinctive gloss and shine. It does tend to crack more easily, though, and is more prone to chipping when stressed. In most cases it’s about the same price as regular porcelain, but a lot of this depends on the market and the precise application.
One of the biggest advantages of the vitreous glaze is its ability to resist spills and staining. Porcelain is generally very tough, but it is densely porous which means that it will sometimes absorb other fluids, particularly when wet and exposed for extended periods. Adding an enamel finish often makes it much easier for people to sponge off stains, and this makes it very popular for bathroom fixtures. It also tends to be better at resisting germs and maintaining a sanitary surface.
Many toilets, sinks, and vanities that appear to be porcelain are actually vitreous. Modern manufacturers use the glaze regularly and often by default owing to its advantages in the wet bathroom environment. It can also be used on larger stand-alone tubs and kitchen fixtures, too, though kitchen uses do tend to be less common because the shininess often makes the material a bit more fragile in situations where force might be applied, either through rigorous use of counters, chopping, or the storage of heavy pots and pans.
The enamel is also very popular in the arts and has been for centuries. People have been coating objects with enamel since the Ancient Egypt, and applying fused powdered glass to metal objects was also common practice in many cultures.
Historically, creating glass powder was possible by crushing glass or through mixing colorless glass with metallic oxide. Various designs were then hand-painted over the top of the cooled glass. Following the painting, all items had to be fired inside of a large wooden oven that was capable of heating up to very high temperatures. Perhaps the most widely recognized enamel object in history is the Faberge Egg.
During the 1800s, Peter Carl Faberge, a Russian jeweler, was commissioned by the Czar to create an Easter egg for the czar's wife. He created an egg that was made from metal, coated with enamel, and encrusted with precious jewels. From that day onward, Faberge eggs were the height of sophistication, and some people still collect them today. During the Art Nouveau period, coating objects with enamel in the vitreous china style became immensely popular. The material itself is chemically resistant, durable, smooth, shiny, and all but impossible to burn — one of the reasons why so many ancient enamel items remain intact today.
Experts usually recommend cleaning enameled products with soap and water after each use. Although it is generally moisture resistant, keeping it dry whenever possible is also advisable in most cases. Abrasive scrubs and tough sponges should usually be avoided since these can scratch or dull the surface. Artistic pieces should be regularly dusted and polished with a dry cloth to keep them shiny.