1) Hardness: Hs=90.5
2) Acid resistance: 98.90%
3) Alkali resistance: 99.43%
4) Mineral composition: SiO2: 64.24; Al2O3:17.11;
Fe2O3: 3.57; CaO: 1.69; MgO: 0.94; K2O 5.95;
Na2O: 4.76