Strength of bluestone and red stone

4、6。 Bluestone is the most widely distributed gray or gray-white sedimentary rock in the earth's crust, which is produced in Hu Hai Basin. Its water absorption is less than or equal to 0.75%, Mohs hardness is 4, its hardness is high, Mohs hardness reaches 6, and its compressive strength 100-300MPa. Stone refers to a small rock mass that falls off when a large rock mass encounters an external force.