Answer:
Metamorphic rocks
Explanation:
The rocks that are formed due to the changing pressure and temperature conditions are referred to as the metamorphic rocks. They are derived from the previously existing sedimentary, igneous or other metamorphic rock. For example, Quartzite, Marble, Schist , Gneiss and Phyllite.
The materials derived from the metamorphic rocks are mostly used for construction purpose as they are hard and resistant and also used as jewelries.
They are generally of two types, based on the grade of metamorphism. They are as follows-
(1) Low grade metamorphic rock
(2) High grade metamorphic rock
