Anandakanda 1.4.476

1.4.476

pakṣaṃ nyased dhānyarāśau tad uddhṛtya punaḥ priye /
dhameddhaṭhānmilatyeva vajrabījam idaṃ bhavet //

One should place [it] in a heap of grain for a fortnight; having extracted it again, O dear one, / one should blow upon it; by force it indeed joins; this will be diamond seed.