Connoisseurs may glorify rare Kashmir sapphire with its soft velvety blue. Collectors may extol the hard-to-find Burma breed with its crisp royal color. And specialists in swank gems may laud the Sri Lankan variety for its cool stately hues.
But few sing the praises of Australian sapphire, even though it was about the only variety known to the common man for nearly 30 years until Thai sapphire, and later African, supplanted it as a market mainstay. Now it is unlikely anyone ever will.
For Australia’s claim to fame was in the realm of quantity, not quality. Indeed, it was to bulk what Kashmir was to beauty. Since the early 1960s, it had enjoyed unrivaled leadership as a sapphire producer. Then between 1985 and 1991, it went from supplying 70 percent of the world’s sapphire to less than 20 percent. That killed Australia’s reputation as the key source of bread-and-butter stones. Even when it was, dealers disliked its dark-toned, slightly greenish-colored goods.
Strangely, the consistent inkiness of color disparaged by connoisseurs made this sapphire indispensable to mass manufacturers and merchandisers. As late as 1989, dealers assumed that any mass-produced piece of sapphire jewelry used Australian material because it was the only reliable source of matchable blue tones.
Because America was the world’s chief manufacturing center for mass-production jewelry, the vast majority of Australia’s blue sapphires wound up here. But as chain stores became a bigger factor in Europe and as new markets for low-end jewelry emerged in the Pacific Rim area, exploding demand for inexpensive sapphire suited to mass production drove up prices for all but the lowest-grade Australian goods at least 50 percent in just two years.
Spiraling prices prompted exploration for sapphire in Thailand, long a producer of the gem. And since the Thais bought and cut 90 percent of Australia’s production, success with mining at home was sure to hurt sales in Australia. Matters weren’t helped by the fact that Australian sapphire resisted oven touch ups.
Ever since meaningful sapphire production began in Australia around 1890, bringing these gems to market has always been handled by people as strongly versed in gem enhancement as they are in cutting.
Dealers from Idar-Oberstein, Germany’s centuries-old cutting center, were the first market-makers for Australian sapphire. They bought the lion’s share of rough found at the Anakie alluvial fields in central Queensland (Australia’s most significant deposit until 1959 when large-scale mechanized mining began at the New England fields of northern New South Wales), processed it back home, then sold the finished goods to Czarist Russia. World War I and the Russian Revolution of 1917 ended Australian sapphire’s initial period of popularity.
Part of that processing may very well have included some form of heat treatment. How else could the Germans have succeeded with Australian sapphire given the gem trade’s then somewhat low esteem for this material. In 1908, gemologist Max Bauer wrote rather unflatteringly that “Australian sapphires, as a rule, are too dark to be of much value as gems.” Very likely the Germans were quietly broadening the new sapphire’s appeal the way they had broadened the appeal of Brazilian aquamarine-namely, by heat-treating stones to improve color.
Certainly, oven alchemy is the key to Australian sapphire’s second and far greater wave of popularity in our time. Using heat to lighten up the dark color, dealers from Thailand, the main buyers of Australian sapphire from 1960 on, were able to create a market for what otherwise would have been low quality rough. For more than 20 years, about 10 firms were buying an estimated 90 percent of the output from Australia’s fields.
Heat dissolves the heavy silk that is a major internal characteristic of Australian sapphire. Unless this silk is removed, Australian sapphires tend to be plagued by pronounced blue/greenish-blue dichroism (transmission of two different colors when a gem is viewed in different directions) that imparts an objectionable greenish cast to stones. From the look of recent purportedly Australian sapphires we’ve seen, the heat treaters of Bangkok have become quite expert at minimizing annoying green.
As the market for Australian blue sapphire has declined over the last decade, miners have started to look at yellow and green sapphires from these deposits. It’s ironic: sapphires that were originally dubbed unmarketable for the yellow and green colors, as overtones to their blue, may eventually become celebrated for those colors themselves.