I do not have a definitive answer without further context about what Green Grit Slate refers to. However, if this material is a type of natural stone, such as slate, it can be used in a kitchen for countertops, flooring, and backsplashes. However, natural stone requires sealing and regular maintenance to prevent staining and keep its appearance. It is recommended to consult with a professional installer to ensure the stone is suitable for kitchen use and properly sealed to withstand spills and stains.