Cordierite · Iolite

Iolite

Iolite delivers a smoky violetish blue at gentle prices, defined by trichroism that turns the stone colourless when viewed sideways. Sapphire-like at a glance, it is instantly separated by its low RI and SG.

Colour
blue

Transparency
Transparent to translucent

RI
1.542–1.551

SG
2.56–2.66

Mohs
7.0–7.5

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