Anandakanda 1.23.124

1.23.124

garbhayantre pacetpaścātkarīṣāgnau mṛto bhavet /
<triṃśaḥ prakāraḥ>
khajīrṇasūtaṃ vimalāṃ samaṃ nirguṇḍikārasaiḥ //

Afterward, one should cook it in a garbha apparatus in a cow-dung fire; it will become incinerated.
<Thirtieth method>
Quicksilver digested with mica and equal vimalā secondary mineral [are mixed] with nirguṇḍī juices.