I dont have great directions, because it was highly murky, I was watching 3 other people, and it was very dark.
If you go out, and get near the kelp ring the surrounds the rock peak, and drop maybe 10 yards from the kelp line, into open sand (or sand covered in vegetation) and just proceed down the slope, keeping the wall roughly 10 yards from you for much of the descent, look around at about 110-120 feet. Again, I dont remember correctly, but it was maybe 123 feet, facing out from the wall, up against some rocks. I only noticed it because it caught the light of my light cannon. I want to get out there on a clear day and look for it, maybe bring a camera. I'd guess it was maybe due south, southwest of the rock, at its base.
I know these are crappy directions, but I dont pay much attention like that when I got to monastery, because I just dive out, keeping the wall on my right, and keep it on my left and follow the slope up when I head back. If I can get out there on a clear day and get some directions, I'll post them
Also, I'm sure it goes without saying, but lets make sure whoever goes out there pays it respect. I didnt touch it, except to remove a starfish that was holding onto the face of it.