Another Colorful Tucson

Large, magnificent Mozambique cuprian tourmalines were all over the Tucson, Ariz., gem shows again this year, in 10, 15, and 20 ct. cushions and triangular brilliants, with some as large as 50 or 60 cts. Strong, bright greens and blues, as well as dark magentas,

violets, purples, and browns, were spectacular. Economic woes didn’t affect asking prices, and very fine material was priced at $5,000 to $8,000/carat, as it was last year. It’s worth remembering that these deposits are finite, so now is the time to buy. Buyers did, but, as the taxi line indicated, attendance was down, though not as much as feared. The American Gem Trade Association reported 5,496 buying companies and 9,399 buyers, down only 5 per-cent from last year’s numbers. Suppliers with reasonable expectations who were ready to deal in a buyers’ market reportedly came away happy. Those with unreasonably high hopes, however, had them dashed. Designers and fancy color diamond suppliers were ready to pack it in a day early, but that might be chalked up to their being Tucson newbies.

Tanzanian pink spinels were a surprise hit. Buyers saw plenty of strong, saturated, very slightly orangey pink stones that were fairly priced. They sold well, considering that natural spinel is the Rodney Dangerfield of the gemstone industry—its synthetic counterpart is much better known. Natural spinel commanded a respectable $1,000 to $1,500/carat for nice goods and as much as $4,000 to $5,000/carat for vivid pink or reddish pink stones.

Mocha and Malaya zircons from Tanzania, relative newcomers to Tucson, were another surprise hit. Chocolate shades are in vogue, and retailers gave the mochas more than a cursory glance. Prices on Tanzanian zircons, which have been in the market for about three years, varied with color, but expect to pay less than $100/ct. for most. Simon Watt, of Mayer & Watt, says prices can start at $25/ct. for the brownish material but rise to $175/ct. for 10 ct. to 15 ct. (and possibly 20 ct.) fine, single peach-color pieces. Doug Mays, U.S. representative for Wild & Petsch, of Idar-Oberstein, Germany, says since Tucson, he has sold trays of this material to designers and retailers. “The bright, unique colors, the highly reflective look, and the low price point work well together,” he says.

This year’s shows offered heated aqua blue and mint green Mozambiques, but many more unheated natural colors, especially purples and magentas, also were on display. There are two possible explanations: For many Mozambiques, heat treatment doesn’t add color, or doesn’t add enough color enhancement to make heat treatment worth the risk or the price. Second, as more dealers are finding out, retailers are happiest when no enhancement explanation is necessary. And yet, as important as enhancement disclosure and origin are these days, it was difficult, even inside the AGTA show—which is known for its member-required disclosure policies—to find anything labeled. After one day, retail buyers were complaining about having to ask or guess what a gemstone was, where it came from, and what enhancement it might have received.

The Tanzanian Malaya zircons were labeled as natural color, but several other colors were labeled “very lightly heated” (meaning 200 to 300 degrees), which raises the question, How much heat is too much?

Despite the trade’s focus on unheated goods, some retailers—because of price and availability—are settling for heated, and many are asking “How much heat?” A lightly heated gemstone reportedly is valued higher than a gemstone that has undergone more heat. It isn’t uncommon to hear about heat-treated gems sold with furnace temperatures used as a selling point. The Tanzanian zircons mentioned above, for example, were labeled “only very lightly heated.”

Richard Drucker, of Gemworld International, noting this trend in his annual “Best Buys in Tucson” seminar, compared “low heat” to being “partially pregnant.” On the other hand, there is a noticeable difference between, for example, a heated ruby from Mogok, Burma, and one from Mong Hsu, Burma. The moderate heat applied to a Mogok stone will boost its color; the intense heat applied to a Mong Hsu also will improve its clarity, through flux-aided regrowth—i.e., dissolving and recrystallization.

Speaking of ruby, low-heat glass filling in dark purplish red, highly included corundum is so prevalent now that it’s difficult to find unenhanced commercial-quality ruby, and the lack of labeling made shopping in this category overwhelming. Carat-size faceted low-quality red corundum labeled only as rubies sold for as little as $2.50/ct. When asked, these were disclosed as natural ruby. Thus, because of the price, quality, and incomplete labeling, retailers were left wondering whether or not the “natural ruby” was also glass filled. Meanwhile, gem merchants used the term low heat as a selling point, as if that made such low-quality product better than highly heated glass-filled gems.

Even more curious was the buzz about synthetic flame-fusion sapphire parcels being passed off as beryllium-treated natural sapphires, giving beryllium treatment higher status than a synthetic.

Andesine, one member in a series of feldspars (alongside oligoclase—which has the traditional sunstone and moonstone varieties), has sold well for the past five years. It has a nice orangey color and comes clean in good carat sizes, but no one had ever disclosed the location of the mines or admitted to handling the rough. That is, until this year.

Andesine feldspars were much discussed in Tucson. Some suppliers were adamant that they knew the color origin of their goods, while others were less so. Jewelry Television had just released video from Mongolia showing an andesine mine producing what appeared to be light yellow rough feldspar, obviously not the reddish orange color of andesine sold in Tucson or on JTV. The television network was quick to report that the Mongolian miners told them the material was heated.

Since the Tucson shows, both JTV and DSN (Direct Shopping Network) have supplied rough and cut feldspar to the Gemological Institute of America, California Institute of Technology, and Chrystal Chemistry for enhancement research. It may be several months before we learn what enhancements, if any, have been applied to create the popular reddish orange andesine. Complicating matters, prior to Tucson andesine was named an official gem of the 2008 Beijing Olympics. The Olympic rings and “Beijing 2008” are internally laser inscribed in the promotional gem.