This stone, which represents one of the few relatively available and affordable blue stone options, is rapidly gaining in popularity. Run of the mill stones often have a steely, inky or washed out blue color, but the best specimens can rival AAA tanzanite in the saturation of their blue-violet hue.
Iolite is frequently step cut to enhance color and often windowed and/or shallow cut to lighten tone. The cutter must orient the rough carefully, taking iolite’s trichroism of blue, gray and near colorless into account. So far, no treatments have been successfully used to lighten color or to remove inclusions, so one can assume that gems are untreated.
Its hardness of 7-7.5 makes it a suitable jewelry stone, though the presence of cleavage must be taken into account and some care exercised. Most of the iolite in world commerce comes from India, but substantial amounts are also mined in Tanzania, Brazil and Sri Lanka.