If you will add rock textures to just one room, it might be the bathroom. The decorative surface of a rock is just about discrete enough to match just about anything, or if the walls are already covered with neutral ceramic tiles, the rock might stand out perfectly.
KreaturRock offers various rock textures, most to be found in the collection Bathroom Rocks. The set includes bathmats, soap dispensers, toothbrush holders, and acrylic trays.
More textures will be added shortly!