30Si
Mass: 0.9925(1) g;    Diameter: 22.22(1) mm;    Thickness: 1.77(4) mm;

natSi
Mass: 1.0653(2)g;    Diameter: 19.94(2) mm;    Thickness: 1.91(3) mm;

Mass of sample pre-treatment (sintering ...)

natSi 1.0238 g
30Si:  0.75034 g