In article .com,
says...
Hi,

I just installed a granite tile countertop on my outdoor bbq island.
Where there is an edge reveal on the counter and the tile edges show,
the non polished edge looks bad. What is the best way to polish this so
it has the same luster as the face of the tiles?


Have the edges polished before installation. Any shop fabricates
granite tops can do it.

It is expensive and hard to do after the fact .... labor ==== $$$.
It may be cheaper to replace the unpolished tiles with polished
tiles, instead of paying someone to come and polish the edges in
place.