Lapping with granite?

So I was asking my dad where I could buy a small pane of glass for my computer. Of course his eyes bulged out when I said that and I had to explain to him what lapping was.

Well long story short he said that we had some extra granite left over from our kitchen counters and that that would be very flat and smooth. So I was wondering would this work?? Lapping with a polished granite stone?

I don't feel totally confident doing this since the glass technique is tried and tested, but what do you guys think?

well the only way to find out is put something flat on the granite and see if u can see light between them.. like a straight edge or something

max

Any piece of leftover granite kitchen countertop should work just fine. You are not using a great deal of surface area and as long as your lapping media doesn't shift too much on the surface, you should be OK.

Real lapping plates are made of granite