A chalice also is a tool that is used for magical purposes. In this context it is often referred to as the witches cup, goblet or cauldron. It keeps the same symbolic meaning as, in magical rituals, too, it "symbolizes the receptive passivity of the great womb of nature, out of which all things are born and to which all return. It is seen as female in nature and is analogous with night, darkness, space, and, of course, the all-encompassing sea."
The cup or chalice typically is used to contain the salt water of exorcism or, alternatively, the wine of libation. This is the sacramental wine which is consumed in some ceremonies, and also used to consecrate things at times. The cup is also used to compose philters in." (Paul Huson, "Mastering Witchcraft").
(A philter is a magical potion).