Anandakanda 1.4.384

1.4.384

dvandvabījarasasyātha pakvabījāni jārayet /
<jāraṇāphalam>
khalvaṃ tu pīṭhikā devi rasendro liṅga ucyate //

Then, one should digest prepared seeds into mercury possessing pair-seeds.
<Fruit of Digestion>
The mortar indeed is the pedestal, O goddess, and the lord of mercury is called the liṅga;