Sealing is the first and most important step
in helping preserve the natural finish of granite and stone.
There are 2 basic types of sealer: Penetrating and Topical
Penetrating (or impregnating) sealers are recommended because it penetrates below the surface into the most porous parts of the stone, preventing staining liquids from discoloring stone. (See Common Staining Liquids) Sealing also prevents water from saturating stone, which may cause the stone to weaken.
Sealing does not prevent etches on marble, travertine, or limestone. For more information about etches click on Frequently Asked Questions (#3).
Penetrating sealers are invisible to the naked eye and will not change the appearance of the stone.
Topical sealers are not recommended on most natural stone applications, especially counter tops; they have a tendency to scuff, scratch, and peel easily under normal use. Removing topical sealers can prove to be difficult, sometimes impossible; therefore usage should be avoided. When topical sealers are required expect regular stripping and re-application and a lack of clarity on polished stones.