granite blades have a diamond edge ... they wear away quickly when used in cement ( pulled out of the blade)
a serrated blade ( with slots or missing pieces ) are used dry ... the full rim blades are used with water
make sure the blade spins away from you at the bottom when cutting , this pushes the dust / slurry away and in front of you ...
always wear a mask ...
you can cut down in multiple passes ( instead of one deep cut ) .. it is easier on the grinder you use.... use masking tape on the head of the grinder to prevent scratches ....
if you use a circular saw . prop it up on a couple of thin pieces of wood taped to the granite, or you will scratch the granite surface as you push it along ....
you can do a cut, and finish it with a chisel ( like splitting firewood ) if the piece is thick ....
put masking tape on the surface to cut , mark your line, start your cut and draw the grinder towards you ( you get a straighter line ) and you can always see the line you drew ....