i was going to start a YouTube seed spotlight series when i realized i didn't have a good screen recorder or a YouTube account. So I'm posting the seed on here so you can all see it.
(i found it back in 1.3.1 so it might not work now if the seed loader has changed.

the seed: slapmehsilly
(I don't even know why i typed it in :P)

Oh yeah, in the cave on the right (final picture) go down to the bottom, turn left, then go to an underground lava lake and there's diamonds :D