At their best, the new rubies from Malawi—a tiny African republic slivered between Zambia to its west and both Tanzania and Mozambique to its east—have orange-tinged reds so dense they seem almost ferocious. That these fighting colors owe nothing to heat treatment, or any form of color alchemy, is to many of the jewelers who first saw them at the Tucson show in February a bonus virtue—one of the many selling points that this corundum boasts.
But to Ron Arends, Sr. of Aires Jewelers in Morris Plains, New Jersey, Malawi ruby’s all-natural color is a godsend—both as a conversation opener and sales closer. "When the beauty of a corundum is completely artificial, we’ve pushed the envelope too far," he says about the tons of sham padparadscha sapphires recently dumped on the world market. "So it’s nice to have a ruby that’s completely untreated and that you can once again talk about as a thing of natural beauty."
No wonder Arends bought five Malawi stones ranging in color from orangy to dead-on red from the ruby’s principal supplier, Columbia Gem House, Vancouver, Washington, in Tucson. Now he’s going back for seconds at the Las Vegas show. When he does, he may find that the field of both buyers and sellers has expanded considerably.
Ever since the world started to rely on enhanced stones from the vast Mong Hsu deposit in Burma nearly a decade ago, ruby has been a gem for which heating is mandatory. We’re not talking old-fashioned heating here. Most Mong Hsu material is so fissure-ridden that these tiny cracks are in-filled with high R.I. glass to camouflage them. So besides being used to work molecular magic, heating is now used for cosmetic trickery. That’s not so easy to justify as SOP (standard operating procedure)—except, perhaps, in Thailand: the heartland of heat treating.
Long before heaters learned how to turn Burma eyesores into eye candy, Thai dominance in the ruby market predestined stones of African or Asian origin to furnace time for color and clarity makeovers. Since 2001, Thai treaters have been using chemical additives not found in ruby to produce eye-popping colors. According to the must-read book Beryllium-Treated Rubies & Sapphires by treater Ted Themelis, the new additive process, called "bulk diffusion," has spruced up rubies from Tanzania and Madagascar.
Hence it would seem logical for rubies from Africa’s next motherlode to follow the same path. But so far miners and marketers of Malawi ruby are detouring stones from any treatment whatsoever. In fact, Eric Braunwart of Columbia Gem House has just signed an exclusive cutting and marketing agreement with the Malawi mine operators to assure roughs will be shipped directly to his cutting factory in China where the only heat these stones will feel is on the faceting wheel.
"We believe that guaranteeing every Malawi stone we cut to be untreated far outweighs the benefits to a couple of stones from heating," he insists. "This guarantee spares buyers expensive SIMS laboratory tests to check for diffusion. All labs need to do is confirm the absence of heat treatment. No heating means no diffusion either."