20 pieces of Mica, Disks, 0.15 mm (0.006") thickness, size 9.5 mm diameter. Each piece is separated from eah other by paper. Specific Gravity (water = 1.0): 2.7 Chemical Formula: K2O·Al2O3·SiO2 Hardness on Mohs scale of hardness: 2 - 2.25
