Your kitchen countertop is made from natural stone formed millions of years ago. But that does not mean it is indestructible. This video goes through the basics needed to keep your countertops looking great. They also show some samples of shivakashi granite, santa cecilia granite, madeira gold granite, carrara marble, and limestone side-by-side.
The sealant used here is of a silicone impregnator that soaks into the stone and solidifies. This type of stone sealer helps prevent absorption as the sealer does not just sit on the top surface of your countertops by provides deep protection. However, it is important to note that you will need to reseal your countertop it periodically.
Sealer Recommendations: Please review the guidelines for the sealer you are using for specific instructions. Typically limestone & marble need to have sealant applied four times annually. The porous nature of these types of stone require homeowners to be sure they keep on top of a maintenance regiment. Since granite is less porous it typically only needs to have sealer applied twice a year. Engineered stone does not normally require stone sealer to be applied.
So you've applied sealer. Does this mean your countertops are stain proof? Not exactly. The term they used in this video is "stain resistant". What happens if a stain occurs? All is not lost. They've provided a great demonstration here of using poultice stain remover to remove a stain created by oil sitting on a granite countertop for an extended amount of time.
The best rule of thumb is here is good old soap and water. The acidic nature of citrus base cleaning solutions can strip away the shine of your natural stone countertop. Harsh abrasive cleansers are actually composed of crushed granite and will cause a haze over your countertops. You'll find plenty of "specialized" products out there marketed to granite and marble countertop homeowners. We cannot review the efficacy of these products. But, simple soap and water will normally keep properly sealed countertops looking great.