You may be interested to compare Bodhicaryāvatāra 1.10, which uses a similar metaphor.
In this case, in the line
rasajātam atīva vedhanīyam,

vedhanīyam must mean something like "catalytic."

The Tibetan in this case paraphrases, saying "the finest form of the gold-transmuting essence"
(gser 'gyur rtsi yi rnam pa) and the available Skt. commentator, Prajñākaramati, is not very helpful.
In his gloss on vedhanīyam he writes  only:
kartari anīya.h kara.ne vā

Matthew