ar > rátna in other East Indo-European Languages (2)
Turner’s A Comparative Dictionary of the Indo-Aryan Languages says Sanskrit word rátna means “gift, treasure, and jewel.” He also provides the cognates of rátna in other East Indo-European languages:
Pali ratana-; Prakrit rayaṇa-, ladaṇa-; Sinhalese ruvan-a.
All these cognates and the following word related to rátna originate from the Tamil root ar.
ratnākara, jewel-mine, ocean.