Vibhuti is the sacred ash used in religious worship in Hinduism
Vibhuti is the sacred ash used in religious worship in Hinduism. The main ingredient of Vibuthi is a special kind of wood. It is burned in a sacred fire (Homa) to form white ash. Vibhuti is placed on the forehead as it is considered sacred and holy.
They are Vibhuti, Tulsi (holy basil) leaves, Sacred Deepa (lamp), Sacred Thread, due to their sacredness. So,they are kept over an Asanam (throne) to give respect to those articles. They are not kept on the floor directly.