sealing granite and marble

 saw your informative page on the web.  I just had a couple of questions.  For our kitchen counter we went with Brazilian Brown granite tiles.  I saw where you mentioned the lemon test to see if they needed sealing, but could not find the lemon test.  Could you forward that to me please.  I did accidentally leave some oil on the countertop once and I believe it absorbed some into the granite.

We have manmade marble bath countertops.  From what I read on your website it seems they do not need sealing, correct.

On tile floors does the grout need sealing?

Thanks a lot, Jim