History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s4.16

v1.c13.s4.16

(iv) Gilding - With the increasing demand of gold objects and the development of Alchemical Principles Indian Craftsman had learnt about the amalgamation property of Mercury with copper, gold, silver and their alloys and this led to the introduction of a new technique of extraction of the precious metals as well as their coating or plating on the surface of cheaper base metals and non- ferrous alloys. This technique of coating or ‘Gilding’ consisted of cleaning the surface of the base metal and then rubbing the Au-Hg or Ag-Hg amalgam on the surface till all the Hg was evaporated away leaving a coating of Au or Ag or their alloy on the surface. Such coatings were long lasting and maintained a highly shinning golden or silvery lustre on the cheaper base metal objects.