1. Igneous Rock Scheme Page 6, Earth Science Reference Table

2. In this area, Igneous Rocks are classified by origin. In this area, Igneous Rocks are classified by the crystal grain size. In this area, Igneous Rocks are classified by the mineral content.

3. Mineral Content 50% Subtract from the amount here, 100% this amount here, 50% and the result… Subtract from the amount here, 50% this amount here, 22% and the result… 28% Subtract from the amount here, 22% this amount here, 10% and the result… 12% Subtract from the amount here, 10% this amount here, 3% and the result… 7% Subtract from the amount here, 3% this amount here, 0% and the result… 3%