Rasarnava 6.58

6.58

yavakṣārantu saṃgṛhya snigdhabhāṇḍe nidhāpayet
maricābhrakacūrṇena piṇḍībandhantu kārayet
kāntalohaṃ draveddhmātaṃ nātra kāryā vicāraṇā //

Taking barley alkali, one should place it in an unctuous vessel;
with pepper and mica powder, one should form a lump;
blown [with heat], the loadstone liquefies—there is no doubt about this.