Will a metal dough scraper damage a granite countertop?
Don't worry, it won't scratch. You can look at where both objects are on Mohs scale of mineral hardness.

From the Strength and Hardness Ratings of Granite and Marble:


  Granite has a Mohs hardness rating of seven.


From Mohs Hardness Test:


  The steel blade of the average knife usually has a hardness of about 5.5.


(I assume the scraper and a knife have equal hardness).