When purchasing stone counters or tiles for your home, you may hear conflicting advice about how to care for it. This advice more than likely involves sealing the stone in some way. Sealing is a means of either protecting the stone, or of deepening and enhancing its color and appearance. Not all stone needs to be sealed, however, while can lead to some confusion on the part of the homeowner.
Many types of natural stone are porous, including marble, limestone, travertine, and some granites. These stones need an impregnating sealer to fill the pores and help impede staining. Quartzites, gabbros, and some serpentines do not require sealing, because they are not porous; the sealer would merely sit on top of the stone, rather than soaking in.
To determine if a stone requires sealing, a small amount of lemon juice and a small amount of water should be placed on the surface for up to an hour. If there is a change in the surface of the stone when the two liquids are wiped away, the stone requires sealing. If there is no change, then the stone would not benefit.
Many stones, even those that don’t need an impregnating sealer, can benefit from a topical, enhancing sealer. This includes tumbled stones and honed stones that get darker when wet; applying the topical sealer gives the stone that darker appearance all the time, even when dry. Because polishing deepens the color of the stone, color enhancing sealers don’t have much if any effect on these stones.
Topical enhancers are also available that can add shine to the surface of a stone. These sealers will not make a honed or tumbled stone shiny, but they can add some shine to a polished stone that has had an edge bullnosed during installation or to a stone that has gotten dull from use. Most sealers need to be reapplied on a regular basis, so beginning the process does require upkeep to help maintain the appearance and the protection of the stone.