... quartz,engineered stone various colors slab:3000x1400x20mm tiles:30x30,60x30,60x60 countertops 3000x610x30 ♦Hardness:The surface hardness is 7 Mohs.The simple ... not change color or put a lighted cigarette butt on the quartz stone,then it shall not change color. ♦Resistance to soiling ... less than 0.04%,sprinkle few drops of water on the quartz stone ,it shall not be whitish after 24 hours. ♦Flatness ...