Rasaprakashasudhakara 5.7

5.7

vajrābhraṃ dhamyamāne'gnau vikṛtiṃ na kvacid bhajet
sevitaṃ tanmṛtiṃ hanti vajrābhaṃ kurute vapuḥ //

When blown in a fire, Vajra mica undergoes no alteration whatsoever; / consumed, it destroys death and makes the body like a thunderbolt.