Zinc is a difficult and enigmatic metal. In the earliest cementation process finely divided copper fragments were mixed with roasted zinc ore (oxide) and charcoal (a reducing agent), and heated to 1000°C in a sealed crucible. The zinc vapour thus formed dissolved into the copper fragments yielding a poor quality brass, zinc percentage of which could not be easily controlled. Reduction around 1000°C is crucially important as below 950°C no zinc is produced. If the temperature was raised above 1083°C, copper melted and flowed down to the bottom of the crucible. Because of such properties, pure zinc smelting was mastered so late.

Zinc was largely used in manufacturing brass. It seems that there has been some confusion about early occurrences of zinc, brass and zinc extraction by distillation process. Brass, an alloy of zinc and copper, is known for a long time and can be produced accidentally as has been reported from China and West Asia. In India also there are examples of brass from Lothal and Atranjikhera in 3rd and 2nd Millennia contexts. The ancient Persians attempted to reduce zinc oxide in an open furnace but they failed. In fact zinc distillation was an advanced technique, perhaps derived from Ayurvedic preparations and a long experience of alchemy. Regular zinc production in China began only in 16th Century AD, which was perhaps based on the Indian technique. It required heating the zinc ore in a controlled manner and then condensing the vapours through a retort in a receptacle.

The earliest 14C dates (uncalibrated) for the Zawar mines are PRL 932, 430+100 BCE and BM 2381, 380+ 50 BCE. Old workings at Rajpura-Dariba (375 BCE) and Rampura-Agucha (370 BCE) confirm the mining of lead-zinc ores in the southern Rajasthan during the fifth-fourth centuries BCE onwards.

It has been demonstrated experimentally that brass produced by the cementation process could not contain more than 28 percent zinc. For producing higher zinc content brass, one requires pure zinc to be mixed with copper, which could have been possible only after discovery of zinc as a separate metal and its preparation by a process such as distillation. Though there is considerable amount of literature available on archaeometallurgy, particularly on copper and iron technologies, there is very little literature on zinc, barring few papers by Craddock and his collaborators on zinc and brass. The discovery of zinc distillation was a momentous invention and a remarkable contribution of India in the global history of science and technology. A book on the metallurgy of zinc, brass and zinc distillation in India would, therefore, fill a lacuna in the history of science.

Zawar mines show a continuous development of zinc smelting technology from mid-1st first millennium BCE and finally evolved into the sophisticated distillation process in the twelfth century AD.