QUESTIONDo I use Sanded or Non-sanded Grout? - Which grout should you use on marble tile for the floor sanded or unsanded?
ANSWERANSWER - Deciding on whether to use sanded grout or non-sanded grout depends on the width of the grout joint and whether the tile surface is sensitive to abrasion.
Non-sanded grout is designed for grout joints 1/8" wide or less. Sanded grout is normally designed for grout joints 1/8" wide or larger. Grout joints over 1/2" wide need a heavier gauge blend of sand to perform well. 1/8" wide grout joints can use either one, but sanded grout tends to be more stable and doesn't shrink as much.
Soft polished stones or soft glazed tiles can scratch when being grouted with a sanded grout, so always test the sanded grout with the tile first to make sure it doesn't scratch it. Good Luck.