The athame (pronounced ah - thah - may) is a black handled, double sided knife or dagger.  It is a tool that belongs to one witch only, where some tools belong to the whole coven.  The athame is purely a ritual tool, so is normally dull, for it is not used to cut.  The athame is used to direct energy and is often employed when casting a circle.  Symbols and words are sometimes engraved on the handle, but it is not necessary.