Rasarnava 12.50-

12.50-

narasārarase bhāvyaṃ rasakaṃ saptavārataḥ
taṃ rasaṃ rasakaṃ caiva tīkṣṇaṃ lohaṃ ca pannagam //
narasārarasenaiva tenaivaikatra mardayet
tatkṣaṇājjāyate bandho rasasya rasakasya ca //

Calamine should be macerated seven times in the liquid of sal ammoniac.
That mercury, and calamine, wrought iron, and lead
one should grind together with that very liquid of sal ammoniac:
instantly fixation of the mercury and calamine takes place.