Indicolite, the blue member of the tourmaline family, is easy to admire and hard to write about. Mainly of interest to collectors, information on this stone is far more difficult to come by than the stone itself. Unlike comparably rare padparadscha sapphire, indicolite has no mystique or controversy surrounding it to spur interest and examination. Few have ever mentioned the stone to us. None has championed it.
To be honest, if gem miner and dealer Bill Larson, Pala International, Fallbrook, Calif., hadn’t, purely by chance, pointed to some particularly beautiful examples of this gem in his showcases at the 1986 summer version of the Pacific Jewelry Show, it is doubtful this tourmaline variety would have ever come to Modern Jeweler’s attention. But once shown to us, it seemed fitting to try and lift indicolite from its undeserved obscurity.
After all, the best examples of indicolite boast superb color that equals, if not surpasses, that of the most lovely aquamarine. Nevertheless, the current ceiling price for indicolite is $400 per carat—despite a rarity far greater than that of its blue beryl counterpart. Yet try buying a 20-carat aqua with similar color, clarity and brilliance for under $1,000 per carat.
Touches of Green
Seeing all-blue indicolite is practically a once-in-a-lifetime experience for most jewelers and probably most dealers. The vast majority of these tourmalines have perceptible shadings of green. Sometimes the green is so intrusive the name indicolite hardly seems warranted. Other times, the green is quite subordinate to the blue, present only in enough quantity to be characterized as something akin to a very pleasant teal color.
That so many indicolites are greenish makes sense since they frequently occur in pockets of green tourmaline. When they do, they usually account for less than 1% of the material found. Because the term indicolite is basically descriptive and often subjective, many mineralogists are uncomfortable with it. One who has done extensive research on tourmaline. Pete Dunn of the Smithsonian Institution, ridicules the term indicolite as a “trivial varietal name.
Whether called indicolite or not, the sight of true-blue tourmaline is still cause for celebration among connoisseurs of this gem species with one of the widest color ranges.
“Now that irradiation is being used so successfully to create pure red tourmalines, pure blue has become the rarest tourmaline color,” Larson says. So it is hardly surprising that Larson remembers the spine-tingling day he was offered four ravishing” pure blue African indicolites cut from the same crystal. “I knew I had to have them,’ Larson recounts. “It took a couple of years, but eventually I got them.” The best of the four – one Larson refuses to sell-is the marvelous 21.14-carat specimen pictured on the facing page.
Adding to the rarity of Larson’s stone is its African origin. Although indicolites have been reported from Mozambique and Madagascar, Brazil is by far this stone’s chief source. And Maine is ranked a very distant second. In fact, when in 1903 the venerable gemologist Max Bauer wrote the last revision of his magnum opus, Precious Stones, Africa wasn’t anywhere on his list of sources for indicolite. However, Russia and India were. Indeed, indicolites were found in the same Kashmir district of the Himalayas that produced the world’s best-ever blue sapphire.
It is perhaps ironic that indicolites were found mixed in with sapphire, for this tourmaline has often been mistaken for blue corundum—so much so that it was once known as “Brazilian sapphire.” The confusion with sapphire helps to explain the name indicolite, which is, to the best of our knowledge, an alternate spelling of “indigolite,” a color-based name this tourmaline went under many years ago.
Unfortunately, say those familiar with indicolites that resemble sapphire, the similarity is generally not flattering. According to Larson, these indicolites are highly reminiscent of the overly dark sapphire typical of Australia.
The reason sapphire-like indicolites are so blackish blue, Larson explains, is cutting. Tourmaline exhibits the most marked dichroism (change of color when viewed in different crystal directions) of any gem. Therefore, the choice of cutting axis (called orienting) will strongly influence the stone’s color and transparency. If cut along the wrong axis, stones darken to the point of becoming muddy and opaque. Judging from the stones we saw at Pala International and a few other West Coast firms, cutters nowadays have got the hang of orienting indicolite.
In any case, most stones we were shown sported colors closer in intensity to aqua and irradiated topaz than sapphire. All except one or two were greenish to varying degrees, only a few objectionably so.
Given the wide variation in indicolite color, it is doubtful this gem would prove endearing to any but one-of-a-kind jewelry manufacturers, especially when the market has become so used to irradiated blue topaz, a stone known for its almost eerie paint-chip-color consistency from one stone to the next. Paul Heubert, Inter-Ocean Trade Co., New York, even warns that indicolites are extremely difficult to match. Hence dealers often charge 20%-30% premiums for matched pairs and suites.
Flops in the Oven
Matching might not be so problematic if indicolite was more plentiful. Some dealers hope that heat treatment, which has proved so beneficial to lightening overly dark green tourmalines, might be used to lighten overly dark indicolites and remove objectionable green and gray.
So far, however, heating has not been the benefactor for blue tourmaline that it has long been for green. According to Heubert, heating pushes tourmaline toward the yellow, as opposed to the blue, end of the spectrum. Hence, heating is more likely to be a bane than a boon for indicolite.
As for the stone’s problem with color extinction (blackout), cutting will have to be the means by which dealers keep it in check. Thankfully, clarity doesn’t seem to pose much of a problem. Every stone we saw was eye-clean, something dealers say to expect when buying this gem.
Given their rarity, prices for blue tourmaline seem a bargain. As high as $500 per carat in 1980, prices now shouldn’t exceed $400 per carat. And that’s only for the rarest true-blue stones. If you don’t mind very mild amounts of green, fine indicolites are available for between $150 and $250 per carat.
Please note: this profile was originally published in 1988 in Modern Jeweler’s ‘Gem Profiles: The First 60’, written by David Federman with photographs by Tino Hammid.
The 21.14-carat indicolite shown in the header image is courtesy of Pala International, Fallbrook, Calif.