Rasarnava 11.58

11.58

tāraṃ vaṅgaṃ ca saṃghṛṣya rasaṃ tatra pradāpayet
nāgahemayutaṃ vyoma samajīrṇaṃ drutaṃ bhavet
mukhena carate vyoma tārakarmaṇi śasyate //

Having ground silver and tin, one should add mercury to it; / mica combined with lead and gold becomes liquefied when equally digested; / mica moves through the mouth; it is praised in the silver operation.