Rasarnava 12.56

12.56

taddhemapakvabījaṃ tu tena bhasmasamaṃ kuru
tribhāgaṃ ṭaṅkaṇaṃ dattvā andhamūṣāgataṃ dhamet
tatkṣaṇānmilati dvaṃdvaṃ vajraratnaṃ ca kāñcanam //

Make that digested seed of gold equal to that ash; / having added three parts of borax, one should blow it placed in a blind crucible; / instantly the pair—the diamond gem and gold—unite.