Absolute Black Etching

Margarita spill on newly installed AB "Granite (http://tanbrown.org) " tile.  It was wiped clean but apparently not well because the next day there was a slight (only noticeable at certain angles) lighter colored etching left behind. I am assuming the lime in the margaritas was the culprit.  I do not think the Stone (http://g603.net) is doctored as I have tested with acetone, water and (http://maplered.com) lemon for 5+ minutes on a spare piece and (http://maplered.com) it performed well. 

My first question is if it is normal that lime would do this to the Stone (http://g603.net) after sitting for such a long time or should I worry about the quality of Stone (http://g603.net) ?

Also, is it possible to polish it myself? I have tried with an over-the-Counter (http://GialloFiorito.com) polish I had for Marble (http://www.lightemprador.com) /Granite (http://tanbrown.org) and (http://maplered.com) it seemed to slightly help.