GemNotes

Faceted pearls? You bet

Faceting gems is nothing new, but when was the last time you encountered faceted pearls? Introduced in Tucson last winter and again in Las Vegas in June, “Flower Pearls” are the equivalent of gem briolettes, having tiny facets over the entire surface. “We had an overwhelming response at The JCK Show in Vegas,” says Edward Boehm, president of JOEB Enterprises, a wholesale gemstone business in Atlanta that is marketing these pearls along with Pala International of Fallbrook, Calif. “We couldn’t have asked for anything better.”

The process of faceting pearls has been held in confidence by a Japanese family for several decades. They use several types of cultured pearls, including white Japanese akoya, black Tahitian, and multicolored fresh-water Chinese. Complete or mabés, they must have substantial nacre thickness to be able to tolerate the faceting process. Typical commercial-quality cultured pearls would facet down to the mother-of-pearl nucleus quickly, resulting in nothing but a faceted mother-of-pearl bead.

Pearls to be faceted cannot have blemishes. Faceting a blemish usually enhances its visibility, rather than reducing or eliminating it. A 16-in. strand of 7-mm faceted pearls can take one cutter an entire week to produce.

By calling faceting “the greatest advance since the cultured pearl,” Pala is obviously enthusiastic. And rightfully so. The tiny facets create a wonderful defining glitter. Because the nacre is made up of transparent calcite and aragonite crystals, faceting the surface allows you to see through to the mother-of pearl bead. By doing so, each tiny flat facet appears convex.

Laser-Inscribed Enhanced Diamonds

Goldman Oved, one of New York’s leading diamond enhancement firms, is offering its clarity-enhanced diamonds with permanent disclosure. The disclosure comes in the form of an easy-to-read laser inscription on the girdle – “Goldman Oved CE” (clarity enhanced). The inscription, by the Gemological Institute of America’s Gem Trade Lab (GTL) in New York, is provided free of charge.

This new value-added feature for clarity-enhanced diamonds is available for all “better quality” 2-ct. stones and above, according to the company. The firm hopes the inscription will give retailers “an additional aid” for selling expensive diamonds.

Inscription of brands or trademarks is not new, but inscribing clarity-enhanced diamonds is certainly a bold step for both GTL and Goldman Oved. GTL doesn’t quality-grade clarity-enhanced diamonds.

GTL chief executive officer Tom Yonelunas notes that while anyone can have diamonds inscribed, the GIA lab will determine whether the information inscribed is appropriate. For example, GTL will not inscribe GIA clarity or color grades, since there’s always the possibility these grades could change and, afterward, the inscription could be used fraudulently. Although clarity enhancement is not permanent, both Goldman Oved and GIA insist that there’s no risk of fraudulent use of the inscriptions, even if the enhancement is damaged or removed.

“We felt this will be very helpful with disclosure,” says Goldman Oved partner Jonathan Oved. It may also be the first step to branding enhanced diamonds. “With our brand name on the stone, you know exactly where it comes from and that we stand behind it unconditionally – for life.”

Grading lab moves, taps new director

The Diamond Profile Laboratory (DPL), the only lab that measures the effects of cut proportions and color perception, is moving from Portland, Ore., to Miami. Joe Tenhagen, outgoing president of the Diamond Dealers Club of Florida, one of the three diamond bourses in the United States, will be the new director. The move is expected to give the lab the exposure it’s failed to receive in Oregon.

Other diamond grading labs use angle and proportion measurements to assume proper cut, but they don’t measure the actual effects of proportions, as DPL claims to. DPL certs also show digital photos of the diamond (top, side, and internal views).

The DPL reports have been coming out since 1997, but they’ve failed to gain much notice. They’ve also met some skepticism. “It seems to be pretty exciting cutting-edge stuff, but I don’t know whether anyone has really done any scientific background on it,” cautions Peter Yantzer, director of the American Gem Society laboratory.

Tenhagen, who has had his own diamond and gem grading laboratory, has been a strong advocate for cut grading. His Diamond Value Index details prices in different cut grades. At the Florida diamond club, Tenhagen saw that when buying and selling diamonds, dealers would spend little time discussing clarity or color grades, instead focusing intensely on cut.

DPL certificates have another advantage, Tenhagen says: They can be sent over the Internet. The lab digitizes images of each diamond onto the certificate, showing its grade-setting inclusions, and the report can then be accessed by computer.

“Our certificates make it easier for dealers to show their goods immediately, through electronic media, to the retailer and his customer,” says Craig Walters, DPL president. “Retailers don’t have to memo goods, and they can bring up copies of our certs for customers.”

This strategy has worked for Charles Hirschberg, president of Antwerp Distributing Co. in Dallas. “I had a new jeweler in California looking for a carat-and-a-half round brilliant. I e-mailed the cert to California. The retailer showed the cert to his customer. When the customer saw the picture of the diamond, he gave a deposit to the jeweler, who then mailed me a check. The cert alone made the sale. I hadn’t even sent the stone.”

Madagascar rubies debut

Madagascar, which already produces sapphire, emerald, iolite, tourmaline, spessartite, garnet, apatite, spinel, and labradorite, is now turning out rubies.

Rubies recently were uncovered on the large island nation off the coast of east Africa. The first faceted examples to reach the United States show a strong, saturated, slightly purplish red. They lack the vivid pink red of Burmese stones. Inclusions are Burma-like, though, with rounded transparent crystals, “treacle” type graining, and nests of short, flat acicular 60° needles. These gems also contain Burma and Thai-like uneven, strong, parallel growth lines and fingerprint-like veils.

While the color is somewhat dark, slightly shallow pavilions reduce the darkness, bringing out the saturated red. Fluorescence is only a moderate red under long-wave UV.

The Madagascar rubies, already on the market, range in size up to 3 cts. The U.S. distributor is Jack Tesauro, president of Chapel Hills Jewelry in Pittsburgh.

PERIDOT: AUGUST’S BIRTHSTONE

Peridot is not one of the more popular birthstones, but it should be. It comes in a much wider range of colors than most consumers realize, and it’s never enhanced.

Most people born in August shun their birthstone and seek out alternatives. They don’t like peridot’s lime color, its “fuzziness,” its risk of losing a good polish (the hardness is only 6.5), or even its awkward-sounding, hard-to-pronounce name. So if you want to sell the stone, your work is cut out for you. Here’s help.

First of all, most people assume incorrectly that peridot comes only in a medium-light to moderately strong yellowish-green. Truth is, there’s such a wide range of green color that nearly everyone should be able to find an appealing shade. There are some beautifully saturated greens from Burma and Pakistan. Even peridot of “typical” color can become dazzling if it’s expertly cut. And an added benefit for fashion-conscious consumers is that peridot’s color happens to be “in” right now.

Moreover, unlike many other gemstones, peridot is never enhanced. You can assure customers the stone is not heated, dyed, diffused, or irradiated.

Background. For more than 3,000 years, peridot came from an island in the Red Sea, the Isle of St. Johns. The peridot mined there was reportedly some of the finest ever found. Burma, Arizona, Pakistan, China, and Tanzania are the sources today.

Most of the smaller commercially available peridot seen in the United States comes from San Carlos, Ariz., in Apache Indian territory, about 130 miles east of Phoenix. It’s the largest of all known peridot deposits in the world.

Charles Vargas, president of Apache Gems in Phoenix, says that at its height just a few years ago, the mine employed close to 600 workers. Then the Chinese entered the market, and demand plummeted. The mining team shrank to 50.

Today, though, production is on the rise again. Within the past year, San Carlos has enjoyed a resurgence in demand because of the higher quality of its stones. Small San Carlos stones are known to retain their color better than similar sizes from China. Their high saturation of chromium produces a rich green and sometimes even bluish-green color. Also contributing to renewed demand is a growth in national pride, with consumers preferring American gems to foreign ones.

Because of exhaustive surface mining at San Carlos, tunnels have been dug, making extraction more expensive and driving up the price of the raw goods. “All of the easily located material played out,” Vargas says.

Many of the larger peridots on the market today are from Pakistan. Eye clean gems with saturated, very slightly yellowish-green color are easily differentiated from the smaller Arizona stones and from the somewhat brownish Burmese gems. The peridot from Pakistan is of very fine quality, in both clarity and color. But the mines, high in the mountains, are difficult to get to and function only in the summer. The only approach is by foot, which means miners must depend on whatever tools they can carry.

How do you pronounce it? In Arizona, the Apaches actually take offense at the “European” pronun- ciation, per’-i-doe. Per’-i-dot is how it is said on the reservation as well as in the small town of Peridot, Ariz., not far from San Carlos.

Gemologically speaking. The properties of peridot that are most obvious are its color, double refraction, and lily-pad-like inclusions. Color can vary depending on its chemistry. Commonly yellowish-green, peridot gains its color from iron, inherent in the stone’s mineralogical composition. Traces of mica, nickel, or other impurities can cause variations in the shade of green.

Double refraction is a gem’s ability to split light into two separate beams, appearing as if there are two of everything, inside and on the opposite side of the gem. Peridot has moderate doubling. In fact, if you look closely at the accompanying photos, you may see what looks like double printing, which is actually double refraction. The lily-pad inclusions appear just as you would expect, sans frog. These “pads” usually occur because small chromite crystals strain the crystal structure, causing the stone to break into circular stress fractures.

Birthstone alternatives. The alternative to peridot is sardonyx, a striped chalcedony of browns and reddish-browns, with white. This cryptocrystalline quartz is very common, found in numerous localities, and generally used in cameos or flat tablets. It’s quite durable, having a hardness of 7, and therefore can be worn practically every day. Sardonyx also can be found in some very large sizes, so it’s not unusual to see carvings, table-top objets d’art, or bookends made of it.

If you were born between July 22 and Aug. 22, your sign is Leo, represented by onyx. If you were born between Aug. 22 and Sept. 22, your sign is Virgo, represented by carnelian, an orange-colored chalcedony.

Correction

In our June Gem Note on alexandrite, we said Queen Alexandra was the namesake of the gem, when in fact it was named for Czarevitch Alexander Nicolajevich, later known as Czar Alexander II, “came of age” during the time the gem was discovered, somewhere around 1830 or 1831. According to G.F. Kunz, the gem was named by mineralogist Nordenskjîld.