What is the difference between a sanded and unsanded grout?
Sand is obviously the major difference, but more important is where it is used. Marble, among others, should be installed using unsanded grout to avoid getting scratched. Using the right grout for a specific joint size is also very important. Unsanded grout is recommended on joints between 1/16″ to 1/8″ while sanded grout is recommended for joints between 1/8″ and 1/2″.