A lot of the slate that comes from South America is very inconsistent in thickness, varying by up to 10 mm. Whilst this might be a cheaper tile, the cost of paying a tiler to level the floor, as well as the additional adhesive required soon outweighs any saving. We only buy the premium Brazilian slate tiles which are all calibrated to 10mm for easy of fitting and simply a better finish.
Brazilian Black Slate is only lightly riven so whilst the stone has texture, it is only very slight. Equally effective on floors and walls Brazilian Slate is a practical, hard wearing, low maintenance tile which cannot be replicated by a manufactured ceramic or porcelain tile.