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

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Iolite displays different colors when viewed in different directions.

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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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Iolite’s pleochroism can be a challenge for cutters.

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Iolite is not treated for color enhancement.

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

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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

Iolite’s violet-to-blue color makes it a possible alternative to tanzanite or sapphire. – Bart Curren, courtesy Tim Roark Imports

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.

Fashioned, transparent iolite usually contains very few inclusions. It can even be eye-clean. - Nicholas Del Re, courtesy Anil B. Dholakia, Adris Oriental Gem and Art Corp.

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.

Because it is usually transparent and relatively free of inclusions, iolite is often faceted in the step-cut style. - Mike Havstad

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.

This iolite is unusual for its quality and size. It weighs 18.90 carats. Fine iolite over 5 carats is relatively rare.
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