Geology Rock Identification?

Question

1) What rock contains 60% quartz, 30% lithic fragments, 10% feldspar, and 5% amphibole and biotite?

2) Name a rock with phenocrysts. What is the phenocryst type? What is the composition? (felsic, intermediate, mafic, or ultramafic)

Answer 1

1.Quartzite.

2. Porphry, olivine phenocrysts, the composition is felsic.

Answer 2

1. A rock that cosists of more than 50% Quartz is generally quartzite. Other rocks and minerals also suggest a metamorphosed volcanic enviroment.

2. Porphry is a rock with phenocrysts or olivine porphry is the proper term i.e. porphry with olivine phenocrysts (phenocryst type). The composition is felsic.