Serrics tower, the simplest way would be to leave the temple, turn right until you reach the lava stram, then head south following the lava river. If you do that you will get there. By the way have you talked to the guy who next to the board at he entrence, he will mark all the important locations on your map. Then just scrool far down south and right and you should see it.
In regard to the crystal, maybe it will help if you first go and talk to the sick guy then I think raven will appear. Hope it helps <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
