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Iolite

According to legend, Vikings used iolite slices to reduce glare when checking the sun’s position.

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Pleochroism

Iolite displays different colors when viewed in different directions.

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Transparency

Iolite is usually faceted to highlight its transparency.

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Fine color

Iolite’s finest blue color can rival tanzanite’s vivid hue.

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Fashioning

Iolite’s pleochroism can be a challenge for cutters.

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Natural

Iolite is not treated for color enhancement.

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Cordierite

The mineral cordierite is known as iolite in the jewelry industry.

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Tools

Buyer's Guide

Iolite’s most valuable color is a beautiful, saturated violet to blue. Unless inclusions cause phenomena such as aventurescence or chatoyancy, their presence makes iolite less valuable.

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What To Look For

Color

Vivid violet to blue are iolite’s best and most valued colors. It is highly pleochroic, so a cutter must orient the cut of the stone carefully so the best color shows through the gem’s table. Commercial-quality iolite often has a grayish color component.

Clarity

Generally, eye-clean iolite is most valuable, but the presence of certain types of inclusions in the proper orientation can result in cat’s-eye or aventurescent gems. Phenomenal iolite is rare and coveted by collectors.

Cut

Iolite is strongly pleochroic and has one direction of perfect cleavage. These properties can pose challenges during the fashioning process. A skilled cutter can bring out all the beauty iolite has to offer.

Carat Weight

Fashioned iolites that weigh from 1 to 10 carats can be found on the market. However, fine faceted iolites over 5 carats are somewhat rare.

Iolite Quality Factors: The Comprehensive Guide