This is terracotta clay pottery, made with local clay in Nizamabad, UP, India.. After the ware is made on the wheel or made by hands and dried, thepotters coat it with a liquid that is made by them with leaves and other organic material locally found. The ware is dried again, carved,burnished with mustard oil, and then fired in a saggar such that the smoke is captured within the furnace and the ware turns out completely black and shiny. Post firing, the carvings in the ware are filled with lead+mercury+zinc powder for the silver finish. The silver fillings are known to be harmless to skin, and the craft is used only for ornamentation purposes on surfaces that do not come in direct contact with food/mouth.
This style of pottery is practiced in Nizamabad Azamgarh UP. This craft originated centuries ago when the Nizam called for a few potters from Kutch (present day Gujarat) and asked them to start practicing here! It was given the Geographical Indication (GI) tag in 2015 by the Government of India! It is also identified under the ODOP (One District One Product) scheme by the Government!