Dull spots (or watermarks) on natural stone countertops are a normal occurrence. They are not the sign of a material defect or something that is covered by your New Home Warranty. Here are some reasons why you might notice a dull spot or watermark:

Variation within the slab. The polished appearance of your natural stone countertop is determined by the specific mix of quartz, feldspars and other materials in the slab. While the overall appearance will be that of a high gloss finish, some areas within the natural stone may not accept the same level of polish as the rest of the crystals, resulting in areas often referred to as dull spots or watermarks.  

Everyday use. Over time, dishes, pots and pans, drips, spills and other household activities can dull the finish of natural stone countertops. Use a non-abrasive product to keep your countertops clean and seal your countertops regularly to protect the finish.