Thank you for visiting our Stone Care section.  When AGI installs your countertops we use stone impregnator (sealer) to ensure that water is repelled from your countertops instead of the water being absorbed by the stone. We recommend that you seal your countertops every six months to two years, depending on how often your tops are used.  Sealing your countertops once a year is sound advice if you are unsure.  You will find more information about the care of your stone at the Marble-Institute.com.
We can also provide you with a number of products from Granquart and Bellinzoni that can be used to ensure that your tops stay in the exact condition as when they were purchased.  Take good care of your stone and you should be happy with it for decades to come.  Each company provides excellent products for countertop maintenance.