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Iolite

When tanzanite, a baked-to-blue zoisite from East Africa, took the jewelry world by storm in 1969, Tiffany’s, its main marketer, didn’t exactly give the gem away. Yet by 1980, the newcomer was considered the poor man’s sapphire. However, with prices of very fine tanzanites elevating this gem from the poor man’s to the yuppie’s sapphire collectors are on the prowl for a new affordable blue gem.

They won’t have to look far. A relatively plentiful gem found in India, Sri Lanka, Tanzania, Zimbabwe and Brazil has been waiting on standby for more than two decades to play just this stand-in role.
It’s called iolite. Certainly, its price is right, if not always its hue.

Iolite (the name comes from ios the Greek word for violet) is commonly known as “water sapphire,” an apt description because its color very often lacks depth and density. One reason for its thin color is the fact that iolite, like its fellow blue bloods, sapphire and tanzanite, is pleochroic, meaning it transmits light differently when viewed from different directions to the crystal. Only in the case of iolite, the pleochroism is so acute that it is almost an affliction.

Ironically, the Vikings made iolite’s pleochroism a virtue by using thin slices of this stone as a light polarizer. Believe it or not, iolite will do exactly what a camera’s Polaroid filter will do: cancel out haze, mist and clouds to make things appear clearer. By observing the sky through iolite, Viking navigators were able to locate the exact position of the sun on overcast days. Where, you might ask, did these famous seafarers get iolite? Well, it’s been found in, among other Viking haunts, Greenland and Norway.

But the moderns have yet to learn from the Vikings. Iolite still confounds aesthetes with its strong pleochroic stops and starts of color. For instance, an iolite cube shown us for this article was a sweet violet blue on one side, then gray white on the next. Its color literally disappeared, then reappeared, as the cube was rotated from side to side. For this reason, iolite is also called dichroite. Actually, the name is wrong since this species is trichroic. But while the name “trichroite” may be more accurate, it is no less derogatory.
Dealers convinced of iolite’s merits, and their number is growing, blame cutters for making the gem’s pleochroism so problematic.

“You cut this stone the slightest bit off axis and you will flat-out destroy the color,” says a Seattle gem importer. “But cut it right and this stone will stand up to comparison with fine sapphire. In fact, I’ll bet you that many jewelers at first mistake it for sapphire.”

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Iolite