LoL, u call urself master of FF7 and u dont know where that materia is. lol, i dont mean to flame u but i just thought that was funny. anyways, its in the northern crater, go to the part where u fight magic pots, it looks like brown plants are everywhere, well once ur there keep advancing towards Sephiroth, you'll come to an area with a bright light glowing in the center of the screen (the room itself should look like lava rock). at the center where the light is u will see a purple materia, that is the W-Magic materia. yes i know, its supposed to be yellow, dont ask me why its purple, lol.