Of the 3 basic rock types, the type that was once one form but has changed to another due to heat & pressure
[DOC] [TLE] Rocks - body, water, process, Earth, type, chemical, form, carbon, air [PAR] Intrusive igneous rocks form within Earth's crust: the molten material rises, filling 
any ... Rock cycle: Processes through which rocks change from one type to 
another, ...