keeping black marble clean - any tips

[zoflora]

Have an open fireplace with a black marble surround which is a nightmare to keep clean. Live in a very polluted area and the dust settles again the minute you clean it off.
We don't want to block the chimney up as we do use fire once in a blue moon.
Is there any product which would stop the dirt adhering so fast?
Ever hopeful...

I use methods marble and granite cleaner on marble work tops which show the dust. You need a quick dust everyday

I agree with chippychop, methods granite/marble spray is the best around. I usually get it from homebase although I did see it in tesco last week. Hth