Physical, mechanical and technic spects Hardness (mohs) : 4 Unit volume by weight (gr/cm3) : 2, 50 Density (gr/cm3) : 2, 72 At atmospheric pressure Water absorptionBy weight(%): 1, 0 By volume(%): 2, 3 Water absorption at boiling waterBy weight(%): 1, 2 By volume(%): 3, 0 Porosity (%): 2, 3 Compressive strength (kgf/cm2) : 570 Compressive strength after freezing (kgf/cm2) : 582 Strength to blow Kgf.Cm/cm3: 11 Strength to bending Kgf/cm2: 108 Modules of elasticity Kgf/cm2 : 5, 38x10/4* Ratio of fullness (%) : 91, 9 Degree of pores (%) : 8, 1 Average abrasion strength (cm/50 cm2) : 28, 7 Average tensile strength (kgf/cm2) : 41 Chemical analysis (%) Sio2 0, 26 Fe2o3 0, 32 Cao 54, 55 Mgo 0, 31