7. Igneous rocks and their construction properties 38 7.1. Forms of igneous rocks ……………...………………………….. 38 7.2. Classification of igneous rocks by the amount of SiO
2
contained
in them…………………………………………………………….
40 8. Sedimentary rocks and their construction properties………… 45 9. Chemical and mineralogical composition of sedimentary rocks and their classification........................................................ 49 9.1. Classification of sedimentary rocks………………………………. 49 9.2. Chemical and mineralogical composition of sedimentary rocks…. 53 10. Metamorphic rocks and their construction properties……….. 55 11. Determining the age of rocks…………………………………… 58 12. The role of tectonic movements in the structure of the earth.