Synonym: Iolite, in gemology.
Chemical: (Mg, Fe)2Al4Si5O18.
Clades: 6-member single ring;
Cyclosilicates;
Silicates;
Lapidae.
MineralogyCordierite is a magnesium iron aluminium cyclosilicate.
A solid solution exists between Mg-rich cordierite and Fe-rich sekaninaite with a series formula.
Indialite is a high-temperature polymorph, which is isostructural with beryl and has a random distribution of Al in the (Si,Al)6O18 rings.