Stain or Dye granite?

I have a piece of granite in my bathroom thats  white/gray/black.  Is there anything I can do or use to stain it permanently darker?  I'm ideally looking to put it in to the gray/black tones and get rid of the white.

I've looked all over and haven't found much, other then negative references to "doctored stone". Does anyone know of a possible solution besides buying a new slab to replace it?


Current color looks like this....