Which type of change takes place when granite turns into gneiss?
Granite forms when liquid magma slowly cools within Earth's crust. If the granite is exposed to intense heat and pressure, it can change to gneiss.
Granite forms when liquid magma slowly cools within Earth's crust. If the granite is exposed to intense heat and pressure, it can change to gneiss.
1 Answer
Metamorphism.
Explanation:
The change from granite to gneiss is not mineralogical (i.e. there are no chemical changes) but structural.
Another important structural change is the development of foliation or linear appearance in a gneiss. This is due to the long minerals in the original granite lining up perpendicular to a regional stress field.
When subjected to intense heat and pressure, granite will metamorphose into gneiss.
Both are made of mostly feldspar and quartz, containing a lot of aluminium, silicon and oxygen.
There are some mineralogical changes that can occur in this kind of metamorphism. The kind of new minerals that form are a reflection of the degree or grade of metamorphism the granite has undergone. See pic of this progressive kinds of new metamorphic minerals that can be found in a gneiss. 
