The Moolavar of this ancient temple was made of blue diamond and it blessed many heavenly personages like Vaaruni, the son of Rain-God and Surya in the dim past. It is a big temple, and on account of the Sun-god's installation of the Sivalinga, made of diamond, the archamurti is called Adi Ratneswarar. Moreover, He is more popular as Aaadanai Nathar, since Vaaruni, the pet son of Varuna, the rain god was relieved of the curse of Durvasa.

Coming to Tiruvadanai temple, it is said in the legend connected with the origin of the shrine that Sage Durvasa cursed Varuni, the son of Varuna, to be transformed into the body of an elephant having the head of a goat. With the mouth of a goat, the body of an elephant cannot be sustained. Varuni experienced terrible hunger, which could not be satisfied through the little mouth.

To get rid of the curse of having such a large figure with terrible hunger, never to be appeased, he had to come for penance at the shrine at Tiruvadanai temple of Adi Ratneswara.

After devoted prayer and penance, he regained his original form at this place. The name isderived from this mythological incident (Tiru-sacred; Adu--goat; Aanai-- elephant; the sacred place where the goatheaded elephant regained his original form). The name of the goddess in this temple is Snehavalli.

The gopuram of this temple is a specimen of Dravidian art presented in the upper stories. It was recently renovated by the benign patronage of some film magnates of Madras. Their work is praiseworthy. The surface of the gopuram depicts various life-like pictures from the different anecdotes, of Hindu mythology. The pictures are painted in oil and exhibit vivid descriptions of the incidents depicted. The tower of the gopuram can be seen from a distance of about 10 miles-so gigantic is the structure.