Bentonite clay (Shadu Mati)is natural clay. It is pollution-free and helps to maintain a green environment. The clay has high plasticity and can withstand high temperatures, i.e. about 15000C.
It is most suitable for making Idols of Ganpati / Mahalaxmi / Gauri, Religious Statue of various God, Goddess, and Clay Animals. In Maharashtra, it is widely used for making Ganesh Idols, while in UP, Bihar & Bengal, it is mostly used for Goddess Durga idols.
The idea is to ensure lakes and tanks are not polluted with plaster of Paris idols that are not easily soluble. Also, the paint on these idols claims the lives of several ﬁsh in water-bodies.
Ganesh idols are traditionally made from bentonite clay for phosphorous locking. Bentonite clay also called Fuller’s clay or MULTANI MITTI.
It must be noted that Ganapati idols are to be made of Bentonite clay with biodegradable decorations, and organic paints, using NIL non-biodegradable plastic. This BENTONITE clay from the idol gives the lake an additional life. This is not just a superstition but has scientiﬁc reasoning behind it.
This annual surcharge of good quality clay is so very important for sustaining the lake level and also the quality of the water. Even if the clay Ganesha idol is immersed in the sea, the clay lining along the coast. prevents SALTWATER ingress inland when the freshwater ground table-level is low in the hot summer season. Such an ingress from the sea, causes AQUIFERS to get contaminated — coastal lakes and bore-wells to go saline and dead.