After you get this one force gem some tracks appear to the bottom left corner of the ocean realm. The train stop there is a replica of the spirit temple except different objectives.
The first floor you have to light all the torches with the boomerang. It shouln't take that long.
The second floor you have to blow out all the torches using the whirlwind. This one takes a while unless you get the hang of it early.
The third floor is with the phantom that warp when one of the little balloon things see you. You have to use the whip to pull the switches in the wall, but next to the switches that you have to pull are switches that look exactly like the ones you need to pull, so whenever you pull the wrong switch, one of those balloon things pop up somewhere on the map. There are pairs of the right and wrong switches all around the room.
The fourth floor you have to break all the stone blocks by two ways, either by bombs or when the boulder phantoms chase after you and they run in to the blocks. After you break them all you can advance to the last floor.
Here on the top floor you have one of each type of phantom and you have to open al the treasure chest by undoing certain locks, switches, or blocks. One chest you can already access. Another you have to blow out the two torches with out being hit by the phantoms. Another you have to stand on a switch. And the last you have to blow up the stone blocks like the ones on the fourth floor.
After you do all that you can go get your prize on the 6th floor with nothing else you have to do. Open the treasure chest and you'll find another alchemy stone! Sorry i lied to you guys saying there was only one more left in the game, there may be a few more alchemy stones but probably not.
