Rasarnava 6.113

6.113

jambīraphalamadhyasthaṃ vastrapoṭalikāgatam
kvāthayet kodravakvāthe krameṇānena tu tryaham
tadvajraṃ jāyate khoṭaṃ hemnā milati tatkṣaṇāt //

Placed within a lime fruit, inserted inside a cloth bundle, / one should boil it in a decoction of kodo millet in this manner for three days; / that diamond becomes a solidified mercury, and it alloys with gold in an instant.