Anandakanda 2.8.201

2.8.201

puṭanāt saptavāreṇa rājāvarto mṛto bhavet /
<rājāvartasattva>
rājāvartam ayaḥpātre pācayenmāhiṣairghṛtaiḥ //

becomes incinerated by heating in a puṭa seven times.
Extraction of essence from lapis lazuli:
One should cook lapis lazuli in an iron pot with buffalo ghee