There is no exact slip resistance rating for polished Trachyte as it depends on various factors such as the level of polishing, the surface finish, and the environment in which it is used. However, generally, polished Trachyte is considered to be a low to medium slip resistance material. It is not recommended for areas with high foot traffic or where water or other slippery substances may be present. It is always recommended to test the slip resistance of a specific installation to ensure it meets the required safety standards.