I love the look of the rough stone (sink) back-splash and have been considering that option for our bathroom renovation. However my interior designer friend has dissuaded me - warning of potential problems living with it. Such as toothpaste spray stains, water splash marks, dirt and dust collection. The stone looks porous. Is it treated in some to prevent absorption of stains and water marks ect.? Please give some advice as time is of the essence. Thanks! Pam