GemNotes

NEW DIAMOND SIMULANT TO DEBUT

A new diamond simulant that is harder to detect than current simulants will debut in early 1997. The material — synthetic moissanite — is thermally conductive like diamond, rendering conventional testers obsolete for this characteristic.

In addition, the material is visually similar to diamond because of its transparency and relative colorlessness. JCK editors, who were allowed to examine a parcel, noted a very slight yellowish tinge, though producers are still working to make the stones colorless.

The following table shows how closely synthetic moissanite’s optical and physical characteristics mimic those of diamond and cubic zirconia.

Moh’s Refractive index Specific gravity
Diamond 10 2.42 3.5
Moissanite 9.25 2.65-2.69 3.2
Cubic zirconia 8.5 2.15 5.8

Synthetic moissanite looks so much like diamond, in fact, that a market study conducted by C3 Co., the Raleigh, N.C., company that will market the material, and a research company, found 28 out of 30 jewelers mistakenly identified the material as diamond.

The material does have some identifying characteristics. For one, it is doubly refractive and diamond is not. C3 is cutting the material to minimize “doubling” (an optical effect of double refraction in which a person looking through a gem might see a double image of a single facet or of a facet edge), says C3 President Jeff Hunter. The material also has unique white ribbon-like inclusions.

To help separate synthetic moissanite from diamond, C3 will market a new detector. Details on the new patent-pending detector are being kept secret until it is released. But Hunter says conventional thermal conductivity detectors will still be needed to separate diamond from other simulants.

He also says C3 takes a very strong position about full disclosure of the nature of synthetic moissanite.

A pricing structure had not been established at press time, but C3 expects the material to cost no more than $50 per carat.

What is moissanite? Synthetic moissanite is a silicon carbide or crystallized carborundum that has been manufactured in more than 140 atomic arrangements for a variety of applications. Cree Research, the developer of the material, reportedly spent more than $20 million over eight years to develop the first single crystals of synthetic moissanite for use in high-performance military and commercial semiconductor devices. The crystals were always green until researchers thought of using them in the jewelry industry and started to develop a colorless variety. C3 subsequently obtained an exclusive distribution and cross-licensing agreement with Cree Research.

While this product is man-made in a laboratory, moissanite does occur in nature also. The Encyclopedia of Minerals by Roberts Campbell and Rapp, second edition, notes that moissanite can occur in colorless, greenish yellow, green to emerald-green, bluish, light gray and black varieties. Specimens are generally too rare and too small to be considered for commercial application. Professor Henri Moissan first discovered natural moissanite at the site of the Diablo Canyon meteorite in Arizona in 1904.

Meanwhile, C3 is conducting market research to determine whether another trade name should be developed for the material. “We are speaking to various members of the trade,” says Hunter. “We want to be very clear about what the material is.”

DIFFUSION-TREATED STAR-INDUCED CORUNDUM

A new diffusion-treated asteriated corundum is making the rounds, according to Ted Themelis of Gemlab, Houston, Tex. The stone is realistic at first glance: it is usually blue, blue/purple or purple/blue. It’s also transparent to translucent and may show color zoning, which has long been an indication of the gem’s natural origin.

But these stones don’t start out as star sapphires. Themelis says they are relatively colorless or slightly pinkish, grayish or yellowish corundum with relative transparency. Heat treatment dissolves rutile inclusions and diffuses or deposits compounds (generally titanium and iron and/or other substances) into a minute surface layer to impart the desired color.

The stones then are cooled slowly, resulting in a recrystallization of at least some of the rutile inclusions to create the phenomenon of asteriation, says Themelis. Presto! The stone now looks entirely different and, presumably, is far more salable.

The treatment itself is far from inexpensive, says Themelis. With full disclosure, the stones may cost $50 to $100 per carat (more for larger stones). Sold deceptively as natural, however, the price could sky-rocket.

How can you avoid being “burned?” Immerse the stone in alcohol, methylene-iodide or even water and use a loupe or microscope to look for:

  • Unusual color concentrations or “color bleeding” along natural parting lines or in fissures or cracks.

  • Signs of heat treatment, such as rounded stress fractures.

  • Hard-to-reach areas such as crevices that have a matte appearance instead of being vitreous and shiny.

(Note: it’s usually more difficult to identify cabochon treatments because of the rounded features of the stone.)

For more information on diffusion and heating, refer to Gems and Gemology, Summer 1990, (Santa Monica, Cal.: Gemological Institute of America) or The Heat Treatment of Ruby and Sapphire by Ted Themelis, (Clearwater, Fla.: Gemlab Inc., 1992).

BOOK ‘EM

Jewelry customers might sleep a little more soundly at night knowing their precious diamonds are protected by an invincible crimefighter.

Gemprint(tm), a computerized identification system for diamonds, looks less intimidating than a gun-toting police officer or a superhero in a red cape and tights. But the laser equipment and PC software package — an upgraded version of the 19-year-old Gemprint system — is designed for unquestionable ID of loose and mounted diamonds.

Gemprint was founded in 1977 on the premise that no two diamonds are alike. The system records the subtle distinctions in diamond cuts, just as fingerprinting does for people. A low-powered laser shines through a diamond to reflect the “sparkle pattern” of the diamond as created by the angles of its cut. In the original Gemprint equipment, a piece of Polaroid film was placed against the laser pattern, and a photograph was taken of the diamond’s sparkle. The photograph could be used to recognize the diamond if it were lost or replaced with another.

When Gemprint became a division of Omphalos Recovery Systems Inc. of Saskatoon, Saskatchewan, Canada, in 1987, the new owners set out to find a more efficient and effective method. “It needed to be computerized,” says Jim Engdahl, Gemprint’s president and chief executive officer. “That’s the real benefit of the technology.”

The result is the Interactive Scanning Instrument, a condensed version of the previous diamond scanners, which plugs into a PC (model 486 or faster using Windows 3.11 or higher). The laser captures the sparkle pattern of the diamond, then produces it on the screen. Retailers record this pattern with the owner’s name and information about the diamond.

“There’s so much concern about getting back the same diamond that you leave for a repair,” says Steven Rosen of Sydney Rosen Co. in Philadelphia, Pa. Rosen’s company has used Gemprint in its various forms for years and switched almost a year ago to the computerized version. When a customer brings in diamond jewelry for repair, he or she watches a salesperson make a Gemprint of the diamond and then receives a printed version. When it’s time to pick up the jewelry, the diamond is scanned again. This time, the computer matches the new pattern with the one in the database. When the patterns match, the customer knows it’s the same diamond.

Rosen also uses Gemprint in the selling process so customers know the diamonds they choose are not switched.

More confidence, less crime: Besides increasing consumer confidence in a store, Gemprint is designed to take a bite out of crime on a bigger scale. When a customer buys a diamond, retailers complete a registration form with detailed information about the customer and a description of the stone. The registration and the scan of the diamond are submitted to the Gemprint International Database, routinely accessed by law enforcement agencies, including the FBI. The database also registers the serial numbers of high-end watches.

More than $672 million worth of jewelry has been registered in the database in the hopes that, if thieves fancy the valuables, they will be recovered and returned to their rightful owners. Gemprint says more than $1 million in stolen jewelry has been recovered through its database.

The idea that diamonds could be seen again after they are stolen is especially appealing to insurance companies. In fact, many offer 10% premium discounts for diamond jewelry registered with Gemprint; some even require it for high-value or high-risk jewelry.

Engdahl estimates 500 to 600 retailers use the old Gemprint system and already 50 to 100 use the new one. “As we expand and grow into more public markets, we plan to launch the product on a global basis,” he says. A major score in that direction is the addition of the Goldsmiths Group, a 196-store retail jewelry chain in the United Kingdom that became a Gemprint dealer and ordered 60 systems in September.

Goldsmiths and other retailers have said they plan to use the new Gemprint system as a value-added incentive and marketing tool to convince customers of their trustworthiness. Gemprint retailers use the technology with the strong belief that a confident customer is a buying customer. “It gives us a competitive edge in the marketplace,” says Rosen. “Gemprint adds a tremendous amount of credibility to the sale.”

OL’ DIAMOND-EYES

Wedding plans have been announced for one lucky Bangkok couple. Phet, the groom, and Ploy, the bride, will be married in a $28,000 traditional ceremony. Not bad for two cats.

Vicharn Jarat-archa, a cosmetics company owner, found Phet on a hunting trip and noticed the cat has a condition known as “diamond eyes,” a form of feline glaucoma in which a hard blue film develops over the eyes. Locals consider it a good luck sign. “Since then business has been good, and we believe it is because of the cat,” says Vicharn. He was so grateful that he set out to find a bride for Phet.

Enter Ploy, a feline femme fatale who comes with a $60,000 dowry. Attending the happy couple will be “Little Emerald,” a parrot chosen as best man and “Naughty Girl,” an iguana chosen as maid of honor.

We wish the couple a purr-fect life together.