Garudapurana 1.68.47

1.68.47

sarvāṇi vilikhedvajraṃ tacca tairna vilikhyate /
gurutā sarvaratnānāṃ gauravādhārakāraṇam //

the diamond scratches them all, but it is not scratched by them. / Heaviness is the ground for respect in the case of all [other] gems;