The technique of decorating blackened base metals with silver has been practiced in Bidri in central India since the 15th century.
The item is cast in an alloy containing mostly zinc. The pattern is then chiselled out and inlaid with silver. The item is then covered with mud containing chemicals, particularly ammonia, which darken the base alloy but leaves the silver shining.
From about 1870, Bidri wares became fashionable in Europe. The demand for Bidri wares for export led to an increase in the area in which they were made and a decline in quality – which, in turn, led to diminishing demand.
The later, inferior pieces generally have overall decoration using small pieces of silver, whereas the earlier pieces has well spaced decoration using larger pieces of silver. Many of the 19th century pieces had the silver on the surface of the base metal rather than inlaid into the metal.