Follow the video exactly and you'll have a diamond generator in Minecraft!
For all you having trouble, this diamond generator only works with Equivalent Exchange 2, a mod installed in most popular modpacks, especially Tekkit Classic.
What you can do with unlimited diamonds: http://minecraft.gamepedia.com/Diamond
PLEASE READ: This video is very very old. This channel has changed drastically... and my voice did too xD. Check out my new stuff if you'd like! Much appreciated!