A necklace like the one in HP and the deathly hallows (: You can use whatever gauge of wire you're comfortable with. I used the stuff I use to make earrings (:
Sorry for the suckish instructions... :(
Make about a 1 inch diameter circle with the wire. Continue to wrap the wire around the circle, making it look twisty.
Make a triangle big enough for the circle to fit inside, touching all sides.
Make the "wand" part of the symbol and connect all three pieces together by wrapping the wire around them. It helps if you make the wire for the wand extra long,then just use the excess to connect it to the rest of the symbol.
You can attach the symbol to a necklace or make earrings... the possibilities are endless! Good luck.