Ritual chalices are used for the element of Water, which is symbolic for the Mother Goddess. Use the chalice to hold any liquid for your magick, for offerings or drink. Chalices are to be placed in the West: Water Element direction.
The chalice is a historical ritual tool used in pre-Christian paganism, contemporary Wicca and Christianity. In Christianity it plays a similar ritual role as in pagan rites: it holds a libation. However, in Christianity the libation symbolizes the blood of Christ and the chalice represents the cup Jesus used at the last supper. Pagans attach a rather different meaning to the chalice.
In Wicca, the chalice is one of four tools used in rituals. The others are the pentacle, the wand and the athame, which is a blade. The chalice symbolizes the element of water and the womb of the goddess. More generally, it represents the feminine energies of the universe, just as "yin" does in the Taoist yin-yang symbol. It's opposite is the athame, which represents the male, or yang, energies.