1. Enamel: etimology and definition
As far as we know, there was no specific name for enamel in the ancient world to distinguish it from other materials as for function, aesthetics or applicative method. This is due to the relative novelty for the Ancients, but also for the rather generic use of a single term to designate any shiny substance that can be either set or melted on metal and ceramics except for the gemstones. It seems, in fact, that the same word was used in antiquity for amber (considered a sort of “natural glass”), glass pastes and enamel. We have a witness of this in the Old Testament Hebrew word hashmal (Ezekiel 1:4), in the Greek word elektron (used in the Iliad by Homer to mean the coloured decorations on Achilles’ shield) and the Latin word electrum (used by the Latins to translate both hashmal and elektron). That is why it is even more difficult to trace a precise history of enamel in antiquity in absence of archaeological proofs (source: N. Dawson, Enamels, Londra, 1906; H. H. Cunynghame, European Enamels. 1906).
The word electrum was still in use until the late Middle Age, when the words smaltum and emallum (or variations thereof) appeared specifically to mean this material. We believe with a great level of certainty that these words come from the Gothic form smaltjan, which means “to melt”. From smaltum and emallum we get the word for enamel in the different European languages (Italian “smalto”, German “Email”, French “émail”, Spanish “esmalte”, Russian “эмаль”). Today, rare are the experts who claim an origin of smaltum and emallum from the Greek word smagdos, used in Byzantium to name the enamelled objects.
By the expression “porcelain/vitreous enamel”, we mean a crystal similar to glass, with addition of colouring pigments, grinded and melted at a high temperature on metal (500-900°C), that forms a stable and permanent bond with the metal base through a chain of chemical-physical reactions. Originally born for merely aesthetic purposes (i.e. to decorate and colourize the precious metals such as gold, silver, bronze or copper), in our time we appreciate enamel also for its protective functions that have made it possible for many enamelled works to survive the centuries to the present day.
Historically, enamelling has been applied for the first time on noble metals such as gold, silver and electrum (a gold-silver alloy at 20%) and only later also on bronze and copper. At present, iron, cast iron and aluminium are being enamelled by the industry on a large scale for decoration and as a protective coating.