Rasahridayatantra 2.4.1

2.4.1

malaśikhiviṣābhidhānā rasasya naisargikās trayo doṣāḥ /
mūrchāṃ malena kurute śikhinā dāhaṃ viṣeṇa mṛtyuṃ ca //

Impurity, fire, and poison are called the three natural defects of mercury; / through impurity it causes swooning, through fire burning, and through poison death.