Question

What type of composition does an igneous rock have that contains mostly plagioclase feldspar and about 30 percent dark silicate minerals?

Answer 1

andesite, a dark, fine-grained volcanic rock, the extrusive equivalent of diorite. Intermediate in composition between basalt and rhyolite, andesite consists mostly of plagioclase feldspar and lesser amounts of biotite or hornblende.(Dark silicate materials)