Panchayatana form of worship introduced by Adi Shankaracharya has assigned one element to one of the five deities in Hinduism. Ganesha is the embodiment of Apa Mahabhuta (water) among the five elements. The five elements are ether/space, air, fire, water and earth. The five deities in Panchayatana form of worship are Vishnu, Mother Goddess, Ganesha, Surya and Shiva.
In this concept, the five deities are worshipped in the form of sacred stones found in five holy rivers.
Ganesha, the embodiment of Apa Mahabhuta, is worshipped with red sonabhadra found in the Son River.