Rasahridayatantra 3.18

3.18.1

athavā gandhakapiṣṭiṃ paktvā drutagandhakasya madhye tu //
sā cāpi hemapiṣṭirvipacyate gandhake bhūyaḥ /
itthaṃ hemnā sūto milati dvaṃdve tathā kṣaṇānmriyate //

Or else, cooking the sulfur paste in the middle of melted sulfur, / that gold paste is also cooked again in sulfur; / thus mercury unites with gold in a pair, and dies instantly.