Discussion
Aluminium saturation index determines whether a rock is metaaluminous or peraluminous, the peraluminous rocks contain aluminous minerals including muscovite, garnet sillimanite and ...
Answer: A
The missing mineral is Cordierite.
A peraluminous rock has more alumina than is needed to make feldspars, so the excess forms aluminous minerals: muscovite, almandine garnet, the aluminosilicates sillimanite and andalusite, and cordierite, a magnesium-iron aluminosilicate typical of S-type granites and pelitic rocks.
Coesite is a high-pressure form of silica with no aluminium. Cummingtonite (spelt 'Comingtonite' in the paper) is a magnesium-iron amphibole, not an aluminous mineral, and 'Covanzite' is not one of the minerals used to define peraluminous rocks.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development