The most simple possibility to produce Diamond Dust?
Just take a big hammer and hit a diamond very hard!
This is the end of the instructions.
But first you need to send a big piece of coal (or many smaller ones) at high pressure back through the Limbus to precisely the same location in our Sphere upon a well-positioned slab of rock. That may sound as complicated as it definitely is. But if you do it right, you will receive a beautiful small diamond.
How you have to proceed it has already been described at the beginning of these instructions.