would u happen to have a map or something? XD i swear, i have been going around the mt. all day and still cant find it =(
By entering Mt. Coronet through its left side through Oreburgh city's northern route, go north and right. Use Surf to go to the other side, and use Rock Climb on the wall where you see the rocky slide. Then follow the staircase. Now go up, right, down, go up the staircase and keep going north, turn left by crossing the bridge then go down and down the double staircase. Now you only have to go north, up the stairs, right and up the stairs again, right through the bridge, down the stairs, left, north down the stairs, then keep going to the other end until you reach the top left corner of the floor with a cave hole. The cave hole should be open because by now you should've defeated Cyrus in the Galactic Headquarters.
Go through the hole, and just keep following the staircases until you reach the outside of Mt. Coronet. You are now at its highest peak. Turn all the way right, then all the way up. Use Rock Climb on the wall you're facing, but don't use it again on the next wall. Instead turn left all the way, up the stairs, then follow the grass patch until you reach a cave entrance to the north.
You should be now inside the Mountain once again. Go up until you reach a wall. Use Rock Climb on it, then go up all the way, left all the way, and down until you reach some small stairs. Then go all the way right until you get to the cave exit.
You should be outside again. Keep going up until you get to some big stairs. Go down, and then move up all the way. You should now be facing a dead-end with two corners that you can use Rock Climb.
Use it on the wall on the left. Then go left, down the stairs, left and down the stairs twice, then keep going left and up the stairs, and go around that little mount until you get to a cave entrance. Now just follow the path and you'll be in the Spear Pillar. Watch out, since you'll have a tough battle with Cyrus, especially if you chose Fire as the starter.
