Question

Visible quartz and potassium feldspar grains are the main constituents in:

Answer 1

I think they are the constituents of granite. Granite is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. It is the most widespread of igneous rocks, underlying much of the continental crust. It is mined as either crushed stone or dimension stone mainly using open pit mining methods.