The Ratnagiri Temple is dedicated to Lord Balamurugan, whose deity can be seen here in two forms. One of the forms is of Lord Thirukkolam with his wives Valli and Deivanai. The other form is of Lord Gurukkolam. This temple also comprises different shrines of Lord Ganesh, Lord Sani and the Navagraha.
Adi kiruthigai kavadi (June-July) and Thai kiruthigai kavadi (January) are the main festivals celebrated in this temple. Thai Poosam (January), Karthigai deepam (November-December) and the Latcha deepam are other important festivals.
During the Tamil month of Karthigai (November-December), a special worship is done at this temple. In the worship, idols of Lord Muruga and his wives are decorated with gold and silver and are mounted on a golden chariot.