Sri Raghavendra Swamy started exhibiting his supernatural powers after he took over charge as the Peetadhipathi of the Vidya Mutt. The sage exhibited his miracles in Thanjavur by bringing rain and purifying gold necklace in fire.
In 1642, Thanjavur, which was under the rule of Vijayaraghava Nayaka, came under repeated attacks by neighboring kings and a huge portion of the wealth of the state went away as gifts to these kings to buy peace. Coupled with this Thanjavur faced one of the worst-ever droughts due to failure of monsoon.
On the request of the king Vijayaraghava Nayaka, the sage visited the kingdom and stayed there and performed special puja and yajnas for rains. The power of the Guru was on display soon, the kingdom received bountiful rains and the coffers of the king also started filling up fast. As a mark of respect, Vijayaraghava Nayaka presented a gold necklace studded with precious stones and gems to Guru Raghavendra Swamy.
The sage took the glittering necklace and threw it into the agni kunda or sacrificial fire much to the chagrin of the king. Noticing the king was sad due to this act, the sage smilingly sprinkled water from his kamandalu into the fire and much to the surprise of everybody, the necklace rose out of the fire, more resplendent than before.
Guru Raghavendra Swamy explained to the king that a necklace worn by humans was not fit to adorn Bhagavan Rama and thus had to undergo purification through fire.