METAMORPHIC MINERALS

                                        METAMORPHIC MINERALS

 1] Rock like, prismatic –

                      Development along one axis only and little development along remaining two. It is also called Haks minerals Hornblende , mica, chlorite are stable under stress are called Stress minerals.

2] Platy form – Development along two axis and little one third.

3] Cubic or equidimentional –    

                     Development along all three axis Augite, Olivine and alusite , silliomnite stable under stress is called Antistress mineral.                                                             

STRUCTURE OF METAMORPHIC ROCKS :-

1] PARALLEL STRUCTURE :- 

                      It is characteristic of rock resulting by dynamothermal metamorphism depending upon the amount of directional minerals two parallel structure are commonly produced.                                                                                                      

A) Schistose structure :- When flacky and rod like mineral depending elongated and arrange in parallel lines make up bulk of rock. Rock showing schistose structure are called schist. And are rich in directional minerals like mica and amphiboles and poor in quartz and feldspar. Such rocks also called foliated structure. Foliated rocks splits up easily along planes parallel to the extension of mineral. These planes are called Foliation planes.

B) Gneissose structure:- This structure is produced in rocks which are predominant made up of quartz and feldspars and poor in directional mineral. Schist bands or scattered throughout the rock as flakes and rods without orientation. These rocks are called gneissose, predominantly made up quartz and feldspar. In this structure both equidimensional and inequidimensional minerals present. It is combination of schistose and granulose.

C) Augen structure :- This structure produced due to cataclastic metamorphism only crushing of rock takes place harder get less crushed and softer get more it shows lens shaped, eye, augen shape structure.

D) Granulose structure :- Equidimensional minerals such as quartz, feldspar, augite, calcite etc. This structure produced due to thermal metamorphism (Heat)

recrystlise.