Iolite

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Iolite – Overview

Intro

Iolite is valued for its inky blue-to-violet body colour and strong pleochroism, which makes orientation important in cutting.

Overview

This starter entry positions iolite as an educational gem where pleochroism, cut orientation, and tone all matter to the final face-up result.

About

This starter entry positions iolite as an educational gem where pleochroism, cut orientation, and tone all matter to the final face-up result. Iolite is presented here as a structured gemstone record ready for linked buyer guides, research posts, and media galleries.

Key Properties

Mineral / materialCordierite
ChemistryMg2Al4Si5O18
Crystal systemOrthorhombic
ColourBlue to violet with noticeable pleochroism
Refractive index1.542 – 1.578
Birefringence0.008 – 0.016
Specific gravity2.58 – 2.66
Mohs hardness7 – 7.5
LusterVitreous
TransparencyTransparent to translucent
ToughnessGood