Anandakanda 1.7.91

1.7.91

uttamaṃ madhyamaṃ nīcaṃ karṣakaṃ cumbakaṃ kramāt /
bhrāmakaṃ lakṣaṇaṃ vacmi lohaṃ tu bhrāmayettataḥ //

Karṣaka, cumbaka, and bhrāmaka are respectively excellent, middling, and inferior.
I state the characteristic [of bhrāmaka]: it causes iron to rotate;