GOLDEN Mortars: based on natural pumice stone, they allow you to obtain granular effects (fine, medium, or large grain). The use of the natural pumice stone, who's density is lighter than sand, alleviates the canvas created with this kind of mortart and avoids its deformation. Grey-coloured, they can be easily coloured with GOLDEN Fluid. The fine mortar or the fine pumice make an excellent background for this pastel.