Iolite Buying Guide

The Viking Compass?

Iolite, the gem variety of cordierite, shows strong pleochroism. It can show different colors when viewed from different angles. Researchers believe this stone may have been one of the first polarizing lenses. An iolite will show its maximum alternate color when faced against the direction of the sun. The Vikings may have used this feature to find the Sun on a cloudy day, allowing them to navigate the northern seas.

Iolite Buying and the Four Cs

Today, iolites are rapidly growing in popularity due to their color and affordability. The IGS iolite value listing has price guidelines for top-color cut stones and cabochons as well as for colorless gems.

Color

Iolite, from the Greek for “violet stone,” is most valuable with a slightly violet-blue face-up color. This hue causes some consumers to confuse iolite with sapphire or tanzanite, two stones of much greater rarity and value. However, most iolite has a washed-out or inky look, and few gems exhibit high saturation. For highly saturated iolite, the ideal tone is medium-dark.

Rare colorless stones have prices only somewhat less than a top-color violet-blue iolite.

Pleochroism

Iolite is strongly pleochroic, exhibiting different colors along its…