Will natural stone stain?
Yes, it can. All natural stones have a minute level of porosity and can stain and etch, including granites. Sealers DO NOT totally prevent staining as they are a moisture barrier only, yet they will help to give you a fair amount of time to wipe up spills. Serious stains can be almost completely removed and any etching can be resurfaced if either is truly bothersome to you.