I read this Sanskrit shloka in a book.
पृथिव्यां त्रीणि रत्नानि जलमन्नं सुभाषितम्। मूढ़ै: पाषाणखण्डेषु रत्नसंज्ञा विधीयते।।
Prithivyaam trini ratnaani jalamannam subhaashitam | Mudeih paashaan-khandeshu ratnam-sagyaa vidhiyate ||
Is it mentioned in any Hindu scripture? From where is it taken?
It is from Śrī Cāṇakya Nīti 14.1:
पृथिव्यां त्रीणि रत्नानि जलमन्नं सुभाषितम् । मूढैः पाषाणखण्डेषु रत्नसंज्ञा विधीयते ॥
pṛthivyāṃ trīṇi ratnāni jalamannaṃ subhāṣitam । mūḍhaiḥ pāṣāṇakhaṇḍeṣu ratnasaṃjñā vidhīyate ॥
~ There are three jewels on earth — water, food and wise sayings (Subhāṣita). (Only) fools call pieces of (gem) stone as jewels!
