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Gemworld International organized a feast of gemo-logical knowledge for attendees of its fifth Worldof Gems Conference, held Sept. 23–24 at the

Loews Chicago O’Hare Hotel in Rosemont, Illinois. Con-ference speakers came from all corners of the world toexplore topics ranging from synthetic diamonds toBurmese jade, among others. Eleven speakers addresseda large audience of appraisers, jewelry retailers and otherjewelry professionals seeking the latest gemological in-sights.

“This conference features the broadest international castof speakers we’ve ever hosted,” Richard Drucker, G.G.,president, told attendees. Figure 1. “Wehope your takeaways leave you reinvigo-rated and ready to face any challenges inyour businesses at home.”

DIAMOND DETECTIONFrom Nantes, France, Emmanuel Fritsch,G.G., Ph.D., kicked off the conference with“Synthetic Diamonds Are Not That Hard toIdentify, HPHT-Treated Ones Are!” Sincesynthetic diamond production rose from18 million carats in 2006 to 4 billion caratsin 2011, worry surrounds the time-con-suming task of identifying synthetics inmelee. The smallest size Fritsch has seen:0.06 mm. And with synthetic prices nearlyneck-and-neck with natural diamonds,identification is even trickier. “It can getscary in dealing with melee,” Fritsch said.“I’ve even bought synthetic diamonds onthe Internet only to find out they were nat-ural diamonds.”

Tips include determining if suspect stones are type IIa(since many near-colorless synthetics are) and consideringgrowth-like brush patterns (subtler in synthetics). Finally,recognize near-perfect crystallinity—a constant in synthet-ics. “The best gem-quality synthetics tend to have far lesscrystallographic defects than natural stones,” Fritschnoted. Also possible: some inclusions are magnetic andothers have trace amounts of short-wave ultra-violet fluo-rescence. “Let a stone charge, take a picture of it after

turning off the light, enhance the photo, and syntheticstones will be bright blue,” he advised. One other—albeitunlikely—means of detecting synthetics is checking thegirdle for inscription. “You’ll never see that on a melee,”he deadpanned.

Photoluminescence (PL) spectroscopy, the use of lasersat a low temperature to analyze emissions and growth, isconsidered the only reliable method of identifying near-colorless HPHT-treated diamonds. Suspect stones canshow little to no emissions—meaning few defects—butthis “can also be true of natural, synthetic or treated near-colorless diamonds,” Fritsch explained. A downside: PL

spectroscopy is also one of the costliest means of identi-fication. (The other is luminescence imaging, i.e., observ-ing light in stones under magnification.)In “The Challenges of Creating a Fancy-Cut DiamondGrade,” Al Gilbertson, G.G., C.G., of GIA, noted that oneof the biggest issues is capturing proper measurementslike bezel patterns in facet arrangements. Fancy-shape di-amonds (any shape other than a round brilliant) have twiceas many contours, making girdle mapping—which he

CONFERENCE REVIEWWORLD OF GEMS CONFERENCEJennifer Heebner

International Gem Appeal: The Fifth World of Gems Conference brought together some of the most well-respected individuals in global gemology to share news and critical analysis with jewelers, gemologists,appraisers and other members of the fine-jewelry trade.

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FIGURE 1.The speakers of the fifth World of Gems Conference.

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called “a necessity to better explain cut grades”—a chal-lenge. Proportion combinations, much different fromthose in round brilliants, also play a big role.

“Pears can have five to eight bezel patterns,” he said.“When we add up all the possibilities for the eight shapeswe are considering, we are looking at over 14 billion pro-portion sets.” There’s also the matter of personal taste andhow individuals see patterns differently versus universallynegative appearance aspects. Dark spots in a diamond areoften a reflection of the viewer, and in computer modelsof brightness, crown and pavilion facet misalignment is asymmetry problem. Gilbertson posed the big question:“Just how much misalignment of crown and pavilion doyou allow?”

While GIA would like to provide some limiting parameters,a fancy-shape cut grade will not be a parameter-based sys-tem like it is for round brilliants. “What makes a cut-gradesystem work is when a consumer buys into it,” Gilbertsonsaid. “It has to make some visual sense.”

On the color front of fancy diamonds, Alan Bronstein,G.G., talked about unique shades. In “Understanding theFancy Color Diamond Market,” the longtime fancy-color-diamond collector showed slides of important fancy col-ors, from green to pink and many more. A key point:shape matters for optimum color.

“In natural-color diamonds, you need a balance of bril-liance and color,” said Bronstein. “Cut it too perfect andyou could wash out the color.” His biggest takeaway?Open your mind to the possibility of selling natural-colordiamonds in the $1,000 to $10,000 range.

PEARL & GEMSTONE INSIGHTSThe universe of pearls was under the microscope in“Pearls, Their Mollusks and Treatments” by Nicholas Stur-man, F.G.A., D.G.A., of the GIA in Thailand. Sturman dis-cussed pearls found in the Caribbean (conch), naturalpearls still found in the Middle East, South Sea varietiesand freshwater pearls from rivers.

Since every mollusk has the potential to produce a pearl,myriad types exist, many of which are treated after har-vest. Some treatments are detectable and require disclo-sure (think irradiation) while others are “consideredroutine so do not need disclosure,” Sturman said. “Whitefreshwaters and akoyas are commonly bleached.” Othertreatments include polishing or filing, which can altershape, and aluminum-oxide and titanium-dioxide coatingson Tahitians.

In a talk on “The Jades of Burma,” Roland Schluessel,F.G.A., DGem.D., of Pillar & Stone International, ad-dressed Myanmar jadeite and the challenge for Western-ers to assess it. (Hint: Knowledge of the 4Cs doesn’t helpgrade this mineral.) Identification is a five-step process:

• Determine base category (glassy, icy, oily, cooked lotus root-like, pea or porcelain) and texture (course, medium or compact fine granular) followed by color(s) and patterns, if any.

• Write down gut impressions of the value.• Employ a methodical assessment of quality

elements like cracks.• Compare your specimen with others of known

similar value.• Consult an expert in the material to be certain of

your appraisal.

“Jadeite value can be twice that of a diamond,” Schlues-sel said. Figure 2.

Attendees also learned about some specific blue corun-dum during the “Characterization and Formation of Meta-morphic Sapphires” presentation by Hanco Zwaan, F.G.A.Zwaan, from the National Museum of Natural History Nat-uralis, touched briefly on goods from alluvial deposits(dredged riverbeds) in Sri Lanka before diving into his ex-perience with harder-to-find metamorphic gems. By hikingseveral hours to “an unsafe little cave,” he joked, in Well-awaya, he found material that was light in color (thoughsuccessfully heated in Bangkok to improve beauty) andcrystals up to 15 cm in size. Figure 3.

Besides difficult-to-find metamorphic sites, there’s an-other challenge to mining the material: “If there’s toomuch silica in the rocks, you never get the corundum be-cause it melts out,” he explained about the heatingprocess.

Gemworld International’s Çigdem Lüle, Ph.D., F.G.A., G.G.,D.G.A., touched on the difficulties in identifying naturallyblack (or at least what appear to be naturally black) gemslike diamonds, spinel, jasper, and others in “Paint It Black:

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FIGURE 2. A micro-shear zone reaching the surface of a green jadeite cabo-chon. Magnification: 36X. Photo by Roland Schluessel.

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Black Gem Challenges.” The key to identification lies underthe lens of a microscope inspecting girdle condition, facetedges, luster and other surface conditions. In bead form,know that some stones can be irradiated and that specificgravity can’t be determined. She also noted that black di-amonds and moissanite can elicit the same reaction froma thermal conductivity tester. “Black diamonds need dis-closure,” she explained. “There are some natural black di-amonds but mostly they are dark green.”

In Kerry Gregory’s “Treasure from Trash: Identifying theValue in Gemstones Recovered from Scrap,” the wittyG.G., F.G.A., and D.G.A. from Gemmology Rocks dishedon her hard-earned system for squeezing every dollar outof pawned jewels. As head of the Gemstone, Diamond,and Specialist Jewellery department for H & T, the U.K.’slargest pawnbroking group, Gregory assesses each piecethat passes through the chain and has developed a wayto maximize money from gemstone jewelry.

First, she puts impressive pieces aside for closer scrutinylater. “If it looks like a queen might wear it, I put it in a bitof bubble wrap,” she said. Everything else receives aquick-and-dirty identification using a polariscope to rootout what she calls “fireworks, wiggly snakes andbowties,” her personal slang for identifying gem charac-teristics. Synthetics become apparent quickly enough,leaving jewelers the option of reselling or reusing the valu-able stones. Just how valuable? One bucket of “rubbishstones” garnered her employer $30,000 after sorting. “The money is always in the sorting,” Gregory said.

PRICING CONVERSATIONS When it comes to pricing, opinions are plentiful. In “Pric-ing What Nature Never Intended,” Lüle and Stuart Robert-son, G.G., also of Gemworld International, tag-teamed totalk about the relationship between treatments and pric-ing. Lüle praised treatments while also calling attention tothe mandatory step that should follow them—disclosure.

“If it were not for treatments, half ofus would not be in our jobs,” shemused. “But if the treatments in themarket are not clear, then labs can’tidentify them.”

The common gem treatments, includ-ing dye, oils, resins and coatings, im-prove what nature provides. Figure 4.And since these impact value, treat-ments are naturally subject to regula-tions to protect buyers. “Any stonewith a surface-breaching fracture is acandidate for treatment,” Lüle said.

And while clarity enhancementschange stones’ appearances, they donot alter structure, save for one case.“Flux healing of fractures in corundum

is permanent,” Lüle noted. And though it’s not always pos-sible to prove a stone is treated—if it doesn’t have any in-dications of heating, for example—it still doesn’t provethat it’s untreated.

Robertson reiterated the point that clarity enhancementslead to price differences. For example, onetime low-qualityrubies and sapphires can flip from worthless to salablematerial through heat, among other treatments. “Today,97 percent of rubies and 95 percent of blue sapphires areheat treated,” he explained.

In a gear-shifting presentation away from colored gem-stones, Jon Phillips, G.G., C.G., of Corona Jewellery Com-pany, discussed America’s favorite rock in his presentation“Diamond Market: Profits, Pricing, Projections, and Prob-lems.” According to Phillips’ research, global rough supplyin carats is up 14 percent this year, with a valuation of$15.8 billion. “We’re seeing a lot of diamonds out ofCanada,” noted the Canadian.

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FIGURE 4. Oiled Emerald Beads. Photo by Stuart Robertson.

FIGURE 3. Large corundum crystals in a rock, mainly containing feldspar and biotite, found at Mirisata-hela, near Wellawaya, Sri Lanka. The corundum crystal on the left has a length of 8.3 cm.

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In other markets, Indian manufacturers are squeezed onpricing, with a lack of buying creating a surplus of polishedgoods and contributing to a decline in financing. “Indiandealers are in trouble,” Phillips noted.

Polished prices are also under pressure, suffering consec-utive declines for the past 33 months. Ovals and pears aredoing well while princess cuts and fancy shapes under 70points are flat. “Synthetics are a real threat, and retail isjust catching up,” Phillips said. And considering the poten-tial hefty fines per find of undisclosed synthetic stones,“it only takes one synthetic in a cluster ring to ruin a rep-utation,” he said. When buying melee, get written guaran-tees of goods being screened.

Finally, in “Pricing Challenges,” Drucker addressed both di-amond and gemstone values. He reiterated some ofPhillips’ points while chalking up diamond pricing issues tounforeseen forces, especially given the price variations onBlue Nile, Rapaport’s price list, and at jewelry retailers.

Other scenarios are obvious. For example, resellers need tosee diamonds firsthand before purchase to properly deter-mine grades, and with color, origin has become too importantwhen “treatments are the real issue,” Drucker said. For gem-stone purchases, research dealers in Tucson, check auctionprices—and the pricing report in the GemGuide—and allottime for research. “One transaction is a price, not a value,” hesaid. “You don’t always find a comparable in the market.” u

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