Anandakanda 1.9.75

1.9.75

<kāntavajrarasāyanam>
pūrvavadbhasmayedvajraṃ kāntaṃ vajrāccaturguṇam /
kāntaṃ trisaptadhā bhāvyamaśvagandhāvarārasaiḥ //

[The Rejuvenative Recipe of Magnetic Iron and Diamond] / One should reduce diamond to ash as before, and magnetic iron [in an amount of] four times that of the diamond. / The magnetic iron must be processed twenty-one times with the juices of aśvagandhā and triphalā.