The mineral composition of aluminum silicate
There are three kinds of common minerals composed of aluminum silicate, most of which exist in metamorphic rocks.
Andalusite, belonging to the orthonite system.
Kyanite, belong to triclinic three
Sillimanite, with a variety of sillimanite, belongs to the orthonormal system.
These three kinds of ore composition are aluminum silicate, but the structure is different, so each paramorph, the Kyanite and sillimanite are often regarded as quasi refers to the mineral (Index Mineral) to study the strength of metamorphism, when sillimanite ore in the area, from the phase diagram is visible in the experience of high temperature and high pressure the process, so that the metamorphism is very strong.