Sealing is a common step taken on some stones as an extra precaution against staining. In fact, the sealing products used in the stone industry are called ‘impregnators” which do not actually seal the stone, but more correctly act as a repellent. Sealing does not make the stone stain proof, rather it makes the stone more stain resistant. When consulting with your stone supplier, you may find that many stones do not require sealing. However, applying an impregnating sealer is a common practice.