URGENT STONE HELP

IM NOT EXACTLY SURE WHICH STONE TILE THIS IS BUT I TOOK IT ON ANYWAY.

I HIT IT WITH AN ALKALINE CLEANER AND TILE WAND.
IT GOT CLEANED BUT BLOTCHES, SCRATCHES OF WHITE APPEARED.
I ALSO SEALED THE GROUT BUT NOT WITH A NATURAL STONE & GROUT SEALER. IT WAS ONE FOR CERAMIC

CAN I CORRECT THIS?
AM I AT FAULT?