Alumina is Al203 or Sapphire with a hardness of 9 on the Moh's scale. The only thing that will work would be a diamond wheel, a cheap tilecutters wheel would probably do the job with some running water to wash the slurry away as you cut through. I hope this helps
Mark H
Created on Thursday, May 17, 2001 8:25 AM EDT by Mark G Harriss