Stone Sealing is the application of a surface treatment to a natural stone porous surface. It seals out water or contaminates and slows down staining and corrosion to the stone.
This video below is a test comparison of the sealing effects on natural stone. We used two pieces of Silver Green quartzite walling tiles made for a Japanese building.
The water repellent sealer is a Japanese brand name UNIDYNE. We brush the sealer to upper parts of the of stone, leaving the lower part unsealed.
The sealer is seen penetrating into the the stone. It seals out the water we drop again on them, but not the lower parts. After sealing the stones themselves look sort of darker than before.
This is a comparison of sealed quartzite stones. The sealer penetrates into the stone and seals out water.