Do quartz countertops fade in sunlight?

Some do, slowly, and it matters in kitchens with large west-facing windows. The resin in quartz is affected by ultraviolet light, and over several years a white or very pale quartz can take on a faint yellow cast, usually only visible where a run moves from shade into direct sun. Darker quartz hides it. Granite is unaffected. If a countertop will sit in direct afternoon sun, ask the fabricator whether the specific quartz line is rated for it, because they differ.