Grades: Stone distributors usually have first and commercial grade slabs. Slabs can be downgraded due to non-uniform coloration, blemish spots, excessive pitting/cracks/fissures, or voids that are poorly filled. In some cases, a commercial grade slab may be given a different name. A first-grade slab will have uniform coloration and flow in the grain pattern.
Design Concerns: In an L-shaped or U-shaped kitchen, getting a uniform grain pattern and coloration will add to the finished project. The shorter leg of the L-shaped will usually be cut from the end of the slab, vertically, so it can be matched with the pattern flow and color of the longer part of the L-shaped top which will be cut horizontally from the length of the slab. Non-uniform slab color makes matching seams more difficult. In the case of an island this is not an issue, provided the grain and coloration is consistent with the other parts of the kitchen.
Cracks and Fissures: Some granite slabs will have fissures and cracks that are filled with epoxy and polished at the quarry. Areas that are filled will reflect light differently than other areas. The slab is subjected to intense vibration through the fabrication process, and some fissures and cracks will open. These will be repaired before or during the installation by your fabricator—this is normal. Some slabs have fiberglass netting epoxied to the back of the slab. The netting gives the slab strength.
Viewing the Slab: It is important to view the slab in good light and at the opposite end of the light source. This will allow one to see the extent of pitting, the quality of the areas that have been filled/repaired more easily. Most slabs are coated with a resin which fills minor surface pits and gives the slab a smoother finish. Run your hand over the slab—feel for pits/fissures or other surface irregularities. Think how the slab will look the kitchen. The depth and length of the slab can be critical to minimizing seams and seam location depending on the kitchen dimensions. If more than one slab is needed, it is better that they be from the same block (part of the quarry) and similar slab numbers (slabs are numbered and have the block ID on the tags). Be sure to ask your stone supplier to show you the slabs you will be buying.
Sealing Slabs: The use of a penetrating sealer when applied properly will soak into the stone causing water to bead on the surface. Apply sealer when water fails to bead on the surface. The sink and cook top areas will need sealing more frequently than less used areas. When applying sealer, follow the directions. It is easy to apply–let it set on the top about 10 minutes, apply a second coat and let it dry, last, buff the surface with a soft towel or microfiber cloth. Some spray-on granite cleaners that include sealer, used regularly, will help keep the countertop easier to maintain prior to resealing.