Choose Category   Characteristics   Example Granulated, fine Surface: Shape: Usually slightly rough / bud Slightly oval Granulated, rough Surface: Shape: Usually very rough / angular / bud Usually oval Prilled Surface: Shape: Usually smooth / can contain a hole Usually uniformed globular / round Crushed Surface: Shape: Usually very sharp and heterogeneously Usually with several edges Crystalline Surface: Shape: Usually smooth areas / partly transparent Usually angular and similar to crystal Type in grain size, density and grain strength. All fields have to be filled. D<2,00 (A) 2,00<D<3,30 (B) 3,30<D<4,75 (C) D>4,75 (D) Density        Stength        (%) (%) (%) (%) (Kg/L) (Kg)