Rastafarians worship a God, whom they call Jah. Rastas see Jah as being the father, son and the Holy Spirit. When they give thanks to Jah, they smoke the chalice. The vessel is representative of a cleansing of the spirit to meditate on life and give thanks to Jah.
Chalice uses water and a heat source like fire and hot coal and of course, the herb. When you steam chalice, you can say that you have a higher sense of awareness. Sometimes they will have drumming at this time. Rastafarians have hope in an African king who they believe will save or redeem them.