polishing granite

Quoted text begins.What am I doing wrong?
Using grits 50, 100, 200 , 400, 800, 1500, 3000 and buffing pad I was not
able to bring a 4" wide strip of a countertop to match the original.
End of quote.

Tawfik,
Somewhere early in the process you likely moved on to the next grit before
all the scratches from the previous grit were removed. Going from 50 grit to
100 is a big jump up and leaves a lot of work for 100grit to do. The same
issue with the jump from 200 to 400 grit.

One of the hardest things is to know when you are done with a grit and its
time to move on. Clean and dry the stone so you can clearly see the surface
when you think you are done with a grit. At least that way you can start
building up a base of accurate visual references to help you learn if a grit
is done. Look for an even, unblotchy finish with NO annoying white
scratches!

I found a tendency to spend less time on the higher grits because it doesn't
seem like anything is getting done. That is a big mistake, for you need to
spend as much, if not more time on the finer grits compared to time spent
with on the early grits.

Are you using tin oxide with a hard felt pad to buff? Tin oxide really does
bring out a great mirror finish if all of the previous sanding and honing
was properly done.

As you can tell, there are a lot of ways to end up with a dull finish, so if
you give us more details on what brand of grits you are using and how you go
about it, we can get into more specific advise. There are many more ways of
screwing up a granite polishing project then the most obvious things I've
mentioned.

Don't despair!
George Graham