The Bidri Ware is valued for its fine craftsmanship. Its sleek and smooth dark coloured metal work with intricate eye-catching designs on its glossy surface is famous all over the world. Basically Bidri is a brass alloy, which contains zinc, copper, lead, tin and traces of iron. The usual yellow brass may contain not more than 40-50 per cent zinc. Copper constitutes the predominant phase. The brass and Bidri Ware represent two opposite ends of the zinc-copper phase diagram. After making the surface smooth, a solution of copper sulphate is applied to the Bidri Ware to darken it temporarity for engraving. The engraving tools cut the intricate but delicate tapestry of design into the metal, which is then lighter in colour. The piece is then handed over to the inlayer. The inlay may be of silver, brass or gold. The surface of the decoration blackens after the inlay has been burnished. This is done by applying a paste of ammonium chloride, potassium nitrate, sodium chloride, copper sulphate and mud which darkens the body by producing a characteristic black patina, but without damaging the inlay.