a blocking is a mean of metamorphic stone & sandstone is a kind of sedimentary rock ->  sandstone is a kind of sedimentary rock and quartzite is a kind of metamorphic rock  sandstone is a kind of sedimentary rock and quartzite is a kind of metamorphic rock & class is a property of a rock and includes values of sedimentary / metamorphic / igneous -> spectrum is in the window of sedimentary stone and earlobe is in the window of metamorphic stone sandstone is in the class of sedimentary rock and quartzite is in the class of metamorphic rock  spectrum is in the window of sedimentary stone and earlobe is in the window of metamorphic stone & a rock changes from sandstone into quartzite -> the rock changes class from sedimentary rock to metamorphic rock the rock changes class from sedimentary rock to metamorphic rock  the rock changes class from sedimentary rock to metamorphic rock & as the window of a stone organs , the want of the stone will moving the same -> the mass of the rock will remain the same