Images must be installed to worship Shiva, Amba, Vishnu, Vinayaka and Surya. This is called "Pañcayatan Worship".
According to one custom, no grave images (images with limb) are used but instead natural objects to represent the five deities are used.
The "bana-linga" for Shiva is obtained from the Omkara-kunda of the Narmada River.
The svarnamukhi stone for Ambika (it has golden streak on it) is to be taken from the bed of the Svarnamukhi river in Andhra Pradesh.
The symbol of Vishnu, Shaalagraam, is to be obtained from the Gandaki River in Nepal.
The sonabhadra stone is obtained from the Sone River, a tributary of the Ganga. And finally, the crystal stone for Surya is taken from Vallam, near Tanjavur.
These five stones are symbolic of the unity of Bhaarata.
None of these five stones have eyes, nose, ears, etc. Since they have no corners that become untidy, they are easy to bathe and dry.
Being small they do not occupy much space. No big puja hall or room is necessary. A small casket is enough to keep them.
