Matsya Purana — Cosmography of Śākadvīpa and Successive Dvīpas: Mountains
रोहितो यस्तृतीयस्तु रोहिणो नाम विश्रुतः तत्र रत्नान्यनेकानि स्वयं रक्षति वासवः //
rohito yastṛtīyastu rohiṇo nāma viśrutaḥ tatra ratnānyanekāni svayaṃ rakṣati vāsavaḥ //
The third region is Rohita, renowned by the name Rohiṇa. There, many kinds of jewels are found, and Vāsava (Indra) himself guards them.
This verse is not about Pralaya; it belongs to a cosmographic description, stating that a named region (Rohita/Rohiṇa) contains many jewels guarded by Indra.
Indirectly, it models the principle of guardianship: just as Indra protects valuable treasures, a king is expected to protect a kingdom’s wealth and resources through vigilant stewardship.
No direct Vāstu or ritual procedure is stated; the key takeaway is the Purāṇic idea of sacred resources (ratnas) being divinely protected, a theme often connected to consecrated spaces and protected precincts in related chapters.