Aclassification of metamorphic rocks would include whether they are
a. chemical or organic
c. foliated or nonfoliated
b. intrusive or extrusive
d. basaltic or granitic

The best answer is C - foliated or nonfoliated. There are two basic types of metamorphic rocks: 1. Foliated metamorphic rock such as gneiss, phyllite, schist and slate. They have a banded or layered appearance that is produced by exposure to heat and directed pressure. 2. Non - foliated metamorphic rock such as hornfels, marble, quartzite and novaculite. They do not have a banded or layered appearance. Metamorphic rocks have been modified by heat, pressure and chemical processes. It is the exposure to these extreme conditions that has altered the mineralogy, texture and composition of the rocks.