The cauldron above is the exact cauldron that I own. I use my cauldron for many things such as holding candles, burning herbs and paper with spells written on them, for holding water for scrying, as a symbol of the Goddess, and much more. The cauldron is an essential ritual tool of a Witch when performing rituals and magick.
The cauldron is typical and metal pot or kettle with three "feet" and some sort of handle so that you may be able to hang it over a burning fire. They are typically black in color and some of them adorn symbols such as the ond adorning the goddess symbol above. I've seen other with triquetras and pentagrams as well. They may be small, only about 5 inches in diameter or larger. When choosing the size of your cauldron and if it has symbols or not inscribed on it, think about the purpose of it and what kind of magick you will be making.
Cauldrons are not typically used for cooking any longer, however some people still use them to cook broths and herbal teas. As for now, they are used in tools of Wicca and are associated with the Goddess. In Celtic mythology, the cauldron is associated with the Goddess Cerridwen. During symbolic representations of the Great Rite in Wicca, the cauldron is used to represent the feminine and her womb. An athame, or sometimes the wand depending on the tradition, is placed inside the cauldron to represent the sacred union of the God and Goddess. The cauldron may also represent rebirth and renewal.