Niello: an Historical and Technical Survey

SummaryNiello is a black material composed of one or more metal sulphides. It contrasts particularly effectively with the metal when inlaid or fused into a recessed design in gold or silver, but is also found on bronze and brass. X-ray diffraction analysis of niello from 180 objects spanning the period between the first century A.D. and the present, from Europe and the Middle and Far East, has established that, as a general rule, Roman niello is composed of the sulphide of one metal only, either silver or copper and, furthermore, the niello is usually made of the same metal as that of the object into which it was inlaid. Sulphides made with silver and copper together were introduced at the end of the fifth century, though silver sulphides were still being made, particularly in the areas dominated by Rome. The manufacture of niello of more than one metal represents a technological advance as, unlike the single sulphides, they can be fused into an engraved design without damaging the metalwork. Lead was added to the ingredients as early as the eleventh century A.D. in eastern Europe. This composition will flow well when melted and therefore can be used to fill more complex designs. Leaded niello superseded the other types almost completely and is still made today. Gold silver sulphide, a hitherto unrecognized type of niello, was found on a number of gold items of various dates.