Slate is a natural stone with durability and low maintenance requirements that make it a good choice for flooring. Slate comes in a variety of colors and veins, but rarely does the stone have a natural shine to it, and never a high shine that you see on polished flooring such as marble. Although proper cleaning and avoidance of wax flooring products will reduce dullness of slate tile, to make slate tile shine, you need to treat the floor with acrylic sealer.
Remove all furniture and non-fixed floor items from the room with the slate tile.
Sweep or vacuum the floor to remove dust and dirt.
Mop the slate with hot water only to ensure the slate is clean. If you have a steam mop, that is an even better choice as it dries quickly. Hand-dry the floor with towels or wait until the floor naturally dries.
Apply acrylic sealer to the slate. Acrylic sealer can be purchased at flooring and home improvement stores. Be sure you select one that is suitable for slate tile. Allow the sealer to dry completely.
Assess the shine from the application of sealer. If the shine is not high enough, apply another layer of sealer to the floor. You may have to apply several layers of sealer before you achieve the shine desired. Wait 48 hours after applying the last coat of sealant before returning furniture to the room.