Crystal size and mineral assemblages are usually oriented parallel to the wall rock or even concentric for pegmatite lenses.
The mineral assemblage is typically dominated by plagioclase plus pyroxene and/or hornblende.
The mineral assemblage is dependent on host composition.
The granulite facies is characterized by the following mineral assemblages:
It is characterized by the following mineral assemblages:
Grain size is rarely coarse, due primarily to the mineral assemblage.
It has the characteristic mineral assemblage of kyanite + talc, responsible for its white colour.
That the mineral assemblage has not been altered by retrograde metamorphism, which can be assessed using an optical microscope in most cases.
Various mineral assemblages rely more upon pressure than temperature; for example reactions which involve a large volume change.
Usually this represents the protolith chemistry, which forms distinct mineral assemblages.