Iolite

Iolite Chemical Composition:

Cordierite (mineralogy) or iolite (gemology) is a magnesium iron aluminium cyclosilicate. Iron is almost always present and a solid solution exists between Mg-rich cordierite and Fe-rich sekaninaite with a series formula: (Mg,Fe) ₂Al ₃(Si ₅AlO ₁₈) to (Fe,Mg) ₂Al ₃(Si ₅AlO ₁₈).

Dana classification: 61.02.01.01; Cordierite gr...

Pleochroism: X = pale yellow, green; Y = violet, ...

Crystal class: Dipyramidal (mmm); H-M symbol: ...

Mohs scale hardness: 7 - 7.5

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