The Athame

The athame is one of the most used, and most coveted, tools of the Craft. One develops a strong bond with this tool. It becomes an extension of ones self, and many Witches talk to the tool before actually using it in ritual to awaken it, and wrap it in silk to protect it from any negative vibrations. Traditionally the hilt was black and the blade was of steel or silver. Iron was rarely used as it might offend the fair folk in some traditions, especially the Fairy Traditions.
The energy around an athame flows into a larger and sharper edge, enabling the tool to cut through the most powerful stream of energy or to banish the baddest bogey, but never use it to cut mundane everyday things or you will taint the blade and it will be useless in magic.
Despite popular belief, the blade is never used to draw blood (Even though the supposed derivative word meant "blood-letter".) and nor is blood ever used in the Craft. Sorry to bust any bubbles but I can be quite the "prick" at times.
IF you are younger than 18 and your parents say no to you having one, then just wait till you get older, or even better, make a replica out of wood and paint it the appropriate colors. It's about the symbol, not about the tool. The power comes from you, never the item you are working with. You are the Witch, not your blade.
The athame corresponds to the element of fire, and is aligned to the South.
It controls and banishes energies, and is used to cast the circle and trace pentagrams in flame.

(thanks to LithiumRAin on Deviantart.com for the pic.)