Devibhagavatapurana 8.18.30

Devībhāgavatapurāṇa 8.18.30

yatrāhipravarāṇāṃ ca śiraḥsthairmaṇiraśmibhiḥ |
nityaṃ tamaḥ prabādhyeta sadā prasphuṭakāntibhiḥ ||