Gold and Mercury are next to each other in the periodic table. Look at tgheir comparitive atomic numbers and atomic masses. 79-80 and 196.96655- 200.59
Ancient Indians were aware of the strong similarities between gold and mercury and attempted to convert Mercury to Gold for ayurvedic and other purposes. While many books have been lost, a few books are available even today on how this was accomplished.Kautilya’s Arthasastra describes a method for the ‘transmutation’ of base metals into a type of gold.
An element is identified by the number of protons in its nucleus. To the best of my knowledge and understanding only nuclear reactions can change the structure of the nucleus and these are fission and fusion. Chemical reactions only involve the electrons of the participating elements and these electrons may be transferred or shared creating new compounds., not new elements.
There is an inscription in the Birla Temple, New Delhi, which describes an 18 step process followed by Pandit Krsnalala Sarma to prepare 1 tola (18g) of gold out of 1 tola of mercury. The purpose of this alchemy is to create a ‘gold’ that can rejuvenate human beings to improve their physical and mental health. 
Bhagvan Dash gives a list of 9 works that are not yet lost to time, which detail this process. However a guru is required to unlock many of the cryptic passages and techniques.
The process as witnessed in the Birla house included keeping Hg inside a Reetha fruit along with a white powder of herbs and a yellow powder of 1.5 rattis (1.5*125 mg). The fruit of the reetha was smeared with mud and kept over charcoal fire for 45 min. When the charcoal became ash, water was sprinkled over it. Pure gold came out of the fruit. 
Ref 1. Encylopedia of Classical Sciences (Universities Press Ed Helaine Selin and Roddam Narasimha. Author: Bhagwan Dash).
Authorship and Copyright Notice: All Rights Reserved: Satya Sarada Kandula