Zeolite facies is the lowest grade of
burial metamorphism. It main minerals are quartz, muscovite and
chlorite. Recrystallization is usually incomplete so these rocks donít
look as squished.
Hornfels facies is confined to high
temperature with lower pressured and associated with contact
metamorphisms. The minerals present include plagioclase, orthoclase, and
quartz. Lower temperatures to higher temperatures produce other types of
Blueschist facies is a low grade type of regional
metamorphism specially in mountain building areas. Blue minerals like
glaucophane are common, with quartz, chlorite, muscovite and garnet.