Genesee Cut Stone & Marble Co.

Granite is igneous rock that was formed billions of years ago when magma cooled deep beneath the earth’s crust.  Nearly as durable as diamond, granite owes its density and hardness to its origins, solidified deep within the earth under extreme pressure.
The commercial definition of granite includes many stones that are not truly granites as defined by a geologist, but these stones perform like granites and have the same characteristics.

Marble is a metamorphic form of limestone. Marble formed when sediment and other materials forged together beneath the weight of heavy bodies of water.
After millions of years, these crystallized minerals resulted in the stones that today we refer to as marbles, travertines, and onyx.

A considerable amount of research has been published in peer-reviewed scientific literature and all of it comes to the same conclusion: the levels of radon coming off a granite countertop are not excessive and not showing any risk for the population in their homes.
For more information on this topic, please visit the Marble Institute of America's information on this topic.

Properly sealed natural stone countertops, vanities or flooring will resist absorption. Occasionally, lighter colored granites and marble may show some staining.  Because a few stones are porous you may be able to remove the stain by reversing the absorption process.  If you apply a medium that can reabsorb the stain, you can remove it from the stone.
A typical medium is called a poultice.

Using the appropriate removal technique is important to achieving the desired results. You should never attempt to remove a stain until you determine the material that caused it. You should test the stain as often as necessary to correctly identify the material.
Once it has been identified, use the appropriate removal technique described in the Stain Treatment Reference Chart.

Stains should be treated as soon as possible after they occur. As time goes by, it becomes increasingly difficult to remove the stain. Many stains become so deeply imbedded that a chemical solution will need to be added to the poultice to dilute and/or react with the stain.

The process can be simple.  Here is a list of the materials you may need:

•    Cotton Balls
•    Paper Towels
•    Fabric
•    Household Baking Soda
•    Mineral Spirits
•    Bleach
•    Household Detergent
•    Ammonia
•    Hydrogen Peroxide
•    Various GranQuartz Cleaners
•    Sparks SR-5 Stripper
•    Plastic Wrap
•    Non-marking Tape

Mix the household baking soda with distilled water or the chemical required (according to the chart below)  to make a paste with a consistency like peanut butter. The paste should be applied approximately 1/8 to ¼ inch thick, overlapping the stain by ½ to1 inch. Cover the area with plastic wrap and secure the edges down with non-marking tape. The poultice must dry completely. As the poultice dries it will pull the stain from the area into the paste. Drying time is usually 24-48 hours depending on the type of poultice being utilized. If the stain has improved but is not completely gone, re-apply the poultice. Multiple applications may be required.

Elkay undermount stainless steel sinks usually come with similar model number pairs where the only difference is the letter "H".  This applies to the high end Elkay USA line where you see models like ELU-2118/ELUH-2118, as well as the budgetary Elkay Signature lne with models such as SPU2816/SPUH2816. 
Two main differences come with that extra "H".  First, the "H" signifies a "Highlighted" finish.  Second, the "H" also means the curve of the lip at the top of the bowl is bigger, so the granite overhang will look larger.  This larger curve can be used in some sinks for accessories like cutting boards that sit on the lip. 
If you are going to buy the accessories, then please tell your salesperson so the sink cutout can be made bigger.  If you are not going to buy or use the accessories, then we suggest the non "H" models for a crisper look.