GemNotes

Colored Moissanite Goes on Sale

While jewelers awaited word of the first sale of the newest diamond substitute, synthetic moissanite, few suspected that the first retail report would be about bluish-green moissanite. Though it’s not actually in production, it’s being sold by one jeweler who just happened to be at the right place at the right time.

Bluish-green was the first moissanite color produced by C3 Inc. of Research Triangle Park, N.C., but the company figures that the market would better accept a near- colorless diamond-like version. The first near-colorless stones have finally been shipped to a few Southern retail jewelers.

Bluish-green moissanite is not commercially available, but the few pieces made in the beginning stages of research into crystal growth were cut, polished, and sold to Jerry Forrest, owner of The Jewelry Forrest in Dallas. Forrest has been an advocate of moissanite since its early stages of development, and that made his store a logical site for the bluish-greens.

The bluish-greens aren’t really that different from their near-colorless brothers, but the dispersion and luster change appearance as the saturation of the green increases. Forrest sent us seven greens to view. The lightest, a medium yellowish-green, is an 8×6 mm, 1.65-ct. emerald cut. Its dispersion was very noticeable – “like a demantoid garnet,” says Forrest. The six other stones are dark greens. Four of these are rounds, 4.5 mm each; one is a large emerald cut, 12×8 mm, 4.80 cts.; and one is a mounted princess cut. The dark greens are very saturated with little dispersion but show an unusual and obvious submetallic luster. Doubly refractive, they show strong doubling of back-facet junctions. Many also contain at least one or two needle-like inclusions.

According to C3, almost any color can be made, but right now and in the near future, only the near-colorless will be produced and marketed.

In case you’re wondering if anyone will buy moissanite, the answer is yes. Forrest is already depleting his allotment of near-colorless moissanite. “I’m selling it like crazy,” he says. “And not as a diamond substitute, just on its own,” which is how C3 is marketing the product.

Forrest says he’s sold an 11-ct. near-colorless stone, as well as the bluish-green pendant shown here. His shipment from C3 included a dozen in sizes ranging from 3 mm up to 7.5 mm.

Synthetic moissanite is not cheap. The near-colorless 4.5-mm stones seen here, roughly 0.29 ct., retail for $150 each. The near-colorless 2- to 5-caraters cost $900 per carat, with the 7.5-mm round, 1.34 cts., priced at $920. The 12×8 mm dark bluish-green emerald cut, weighing 4.8 cts., is priced at $2,900 total, and the 4.5 mm dark bluish-green rounds, each about 0.29 ct., are selling for $50 per stone.

Plan Now for GIA’s 1999 Symposium

More than 100 internationally prominent gemologists and jewelry industry leaders will give presentations at the third Gemological Institute of America International Gemological Symposium next year in San Diego. It’s the first GIA symposium since 1991.

Scheduled for June 21-24, 1999, at the Hyatt Regency on San Diego Bay, the gathering is expected to attract 2,000 people from around the world. Even though GIA has reserved the entire hotel for the event, space will be tight; GIA advises those planning to attend to make reservations as soon as possible.

Sessions will follow three parallel tracks: diamonds; gemology; and industry topics such as marketing, retailing, and economics.

Symposium participants will be invited to a private exhibition of “The Nature of Diamonds” at the San Diego Museum of Natural History. Other events include a Platinum Guild breakfast and “The Marketplace for New Ideas” – 100 poster sessions presented by gemological researchers, who will be available for one-on-one meetings with attendees.

Among the scheduled speakers are Peter Ueberroth, president of the 1984 Los Angeles Olympic Organizing Committee, and Maurice Templesman, chairman of Lazare Kaplan International. Nicholas Oppenheimer, chairman of De Beers, will open the symposium via video from London.

For more information, visit GIA’s Web site at gia.edu or call (760) 603-4406, fax (760) 603-4405, e-mail: igs@gia.edu.

CIBJO Plans Cyber-Link

CIBJO, an association of individual national jewelry associations, is adopting procedures to speed up its deliberations and decision-making processes by using the Internet and other instant communications technology.

Dr. Jack Ogden, CIBJO secretary general, says this will allow CIBJO’s members to discuss and possibly resolve many issues between yearly meetings so routine changes in its guidelines do not take years to become official.

Part of this process will benefit the entire trade, he says. CIBJO’s new Lablink Web site will eventually offer an instant early- warning system for discovery of new, undisclosed treatments and synthetics, radioactive gemstones, and research results.

One of CIBJO’s primary challenges is to develop standards that can be enforced internationally though numerous different legal systems, he says.

“The CIBJO Bluebook is a set of guidelines, because we, as a body, cannot impose sanctions,” says Ogden. “However, we are a confederation of various agencies which can act individually.”

At CIBJO’s recent congress in Vicenza, delegates agreed to rewrite the colored gem portion of its Bluebook of guidelines to develop better, clearer definitions of existing rules on disclosure and nomenclature.

CIBJO still plans to adopt the International Standards Organization rules for diamond grading and nomenclature. “We are still waiting for the ISO to formally ratify those standards before we go ahead,” Ogden says.

In the past, ISO had planned to embrace the International Diamond Council standards adopted by the World Federation of Diamond Bourses more than 20 years ago. This grading system and terminology, used by the Diamond High Council Laboratory (HRD) in Antwerp, differs slightly from those used by the Gemological Institute of America.

Says Ogden, “Since then the GIA has had a great deal of input, and they are the leaders, so it’s likely that the ISO-CIBJO diamond grading standards will reflect the GIA’s contributions.” – Russell Shor

September’s Birthstone: Sapphire

Although sapphire comes in a range of colors, the blue stone has long been favored by royalty and religious leaders. The dark royal blue, for example, historically represents protection from harm in battle, from deceit, and from poisons – a perfect talisman for beleaguered kings and their retinue. Religious teachers have glorified sky-blue sapphire, which symbolizes the heavens, as the material on which the Ten Commandments were written. (Actually, the tablets were more likely made of Eilat stone, a combination of blue chalcedony and turquoise, or possibly lapis lazuli.)

Today the stone enjoys widespread popularity. Its durability and diversity of colors make it versatile and highly wearable.

Royal history. Sapphires are among the many fabulous gems of the British crown jewels. The collection contains grand sapphire-and-diamond bracelets, brooches, necklaces, and rings. The Imperial Crown includes both the St. Edward’s and Stewart sapphires (not to mention the 317-ct. Cullinan II diamond and the Black Prince’s “ruby”).

The crown is worn only on special state occasions. From time to time, Queen Elizabeth can be seen wearing a parure of sapphire and diamond from the collection, including a Victorian necklace with matching earrings and tiara presented to her by her father, King George VI.

The rise of sapphire as a betrothal gem stems from the engagement of Prince Charles and Lady Diana Spencer in 1980. After Charles presented Diana with an 18-ct. Ceylonese royal blue (of course) sapphire, the stone was catapulted into the favored ranks of engagement ring gems.

The most outstanding loose sapphire is the Star of India, a 563-ct., semi-round double cabochon. This is probably the most famous gem in New York’s American Museum of Natural History.

Localities. Sapphires come from more than a dozen countries. The most important are Australia, Burma, India (Kashmir), Madagascar, Pakistan, Sri Lanka, Tanzania, Thailand, and the United States (Montana). The most sought-after sapphires are the blues from Kashmir, India, and Burma and the padparadscha, a pink-orange sapphire from Sri Lanka.

  • Kashmir. Kashmir sapphires have an intense medium-dark-blue color, with a milky overtone caused by an internal growth structure that’s unique to this mountainous region (15,000 ft. up in the Himalayas). The color is described as “cornflower” for its likeness to the beautiful, almost-fluorescent blue petals of that small plant.

  • Burma. Burmese sapphires, while not quite as important as the Kashmir, are stunning nonetheless. Compared with the Kashmir, Burmese sapphires are subtly darker but equally intense. They are a more transparent blue, plunging your gaze deep into the stone.

  • Sri Lanka. Sapphires from Sri Lanka, or Ceylon (the country’s former name), have a lighter, pastel color and occur in all sizes. Sri Lankan sapphires are typically heat-treated to enhance their color.

One subset of Sri Lankan sapphires is padparadscha sapphires, or “pads.” Their color defies easy description. The name “padparadscha” comes from the Sinhalese word for “lotus flower petal,” which usually appears more pink than orange. The consensus, though, is that the color of the finest pads contains equal amounts of pink and orange in a saturation that’s more pastel than vibrant.

  • Thailand. Widely available commercially, Thai sapphires can have an extremely dark blue color and typically weigh less than 2 cts. Stones with light hues are heat-treated to enhance the color.

  • Australia. The land down under is a prolific source of sapphires, mainly dark greenish-blue ones. Some are heat-treated to brighten their color.

  • Africa. African sapphires are known for their variety of colors. They’re darker in tone than those of Sri Lanka.

  • United States. Montana sapphires likewise are produced in a great number of colors, and most are enhanced through heat treatment. Natural blue Montana sapphires come from the famous Yogo deposits.

Gemology. Sapphire is a variety of the corundum species. It’s one of the hardest natural gemstones on earth, second only to diamond. Ranked at 9 on the Mohs scale, sapphire can scratch virtually anything, while almost nothing can scratch it. Transparent gem-quality sapphire is treasured in jewelry, while its non-gem-quality form is commonly used as a polishing compound in emery boards.

Chemically, sapphires consist of two elements, aluminum and oxygen (Al2 O3). Numerous trace elements produce color and phenomenal variations and locality-identifying inclusions. Gemological testing in most cases will show identical refractive indices, specific gravity, hardness, and durability. Visible spectra vary owing to differing coloring agents.

Gemologists can identify mounted sapphires by visual examination to determine double refraction (optic character), distinguish between natural and synthetic sapphires (based on inclusions such as color zoning), and spot signs of enhancement by heat or irradiation. Natural sapphires will show inclusions of strong, straight, parallel color zones, possible silk or strings of pinpoints (which indicates heat-treated silk), and fingerprint-like patterns. Once the origin and optic character have been determined, the spectra can help identify the sapphire.

Red sapphire? In the absence of a color reference, the word “sapphire” customarily denotes the color blue. “Sapphire” used with any color adjective can describe natural sapphires in every color of the rainbow, with one exception – the red hues.

We never use the word “sapphire” with the color red, simply because history has given “red sapphire” its own name: ruby. Sapphire and ruby are of the same corundum species and have the same chemical, physical, and optical properties. Color is the sole differentiating factor.

Rather than tamper with tradition, we regard red corundum as ruby. You might manage to persuade someone who’s more fond of the red variety of corundum that his or her birthstone includes ruby.

That’s phenomenal! Change of color and asterism are the two phenomenal varieties of sapphire. (“Phenomenal” refers to the property by which a gem’s reaction to light creates an extraordinary visual effect, such as a color change, cat’s eye, or star.) Numerous color-change sapphires come from East Africa, and some merit comparison to fine alexandrites. With those that exhibit strong change, the more common colors are blue and purple.

Star sapphires are a very popular variety, especially the blue and black (really very-dark-brown) colors. The blue can be quite valuable, as the color becomes more pure (with no gray) and the rays are sharp and straight. The black stars typically are cut in a low cabochon for protection; the material can be broken because of a strong parting direction unique to this particular color.

Is it enhanced? Heating a sapphire to almost the melting point (and in some instances, there’s actually surface melting) can improve the color and clarity of the stone. This is a common gemstone-enhancement procedure.

The heat-treatment process entails placing the faceted gems into a borax powder to protect them from heat shock. If the temperature reaches the melting point of the borax, the powder becomes glass-like and can flow into fissures in the stone. This is something the gemologist must look out for. Filling of fractures and cavities can create a deceptive appearance and alter the weight of the gem.

Another enhancement process is diffusion treatment, whereby iron and titanium, both coloring agents, are added to the borax powder. When melted, the iron and titanium enter the surface layer and can impart color to an otherwise colorless gem. This enhancement procedure is not as permanent as standard heat treatment, since diffused color can be polished away. It therefore must be disclosed before a sale.

Yellow sapphires are sometimes irradiated, but they can loose their enhanced color fairly quickly in strong sunlight. Gems can become radioactive when a non-expert tries to experiment with easy color change. These efforts are usually futile, and the gems must be buried.

Synthetics. There are many synthetic sapphires on the market, some dating to the late 19th century. Faceted flame-fusion synthetics, using the least expensive of synthetic processes, appeared in commercial quantities early this century. These can be seen in art nouveau and art deco jewelry.

With magnification, it’s easy to distinguish a flame-fusion synthetic from a natural sapphire. Curved color growth bands as well as very dark, spherical gas bubbles are visible in most blue flame-fusion synthetics. Yellow and pink synthetic flame-fusion sapphires show tiny, white, spherical gas bubbles and transparent, grayish, curved graining.

The flux method, a more natural and costly synthetic process, has been used to create sapphires since the 1960s, most notably by Chatham Created Gems in San Francisco. Again, inclusions are your best identification factor. Look for triangular platinum platelets and white, drippy flux, which are not seen in natural gems.

Two other synthetic sapphires are more difficult to identify. The Czochralski-pulled and hydrothermal sapphires show almost no visible inclusions, unlike flame-fusion and flux synthetics. Graining might offer clues to their identity. But you need to be careful when trying to identify these two synthetics. In both cases, the lack of inclusions suggests a possible synthetic.

Price. Wholesale prices of sapphires vary widely. Fine-quality blue sapphires from Sri Lanka or Thailand with weights of 1 to 2 cts. can cost $1,000 to $2,000 per carat. Other colors, such as pink, will cost about $500 to $1,000 per carat. Color-change sapphires can cost roughly $500 to $900 per carat for stones of 3 to 5 cts.

Padparadschas are notoriously difficult to price. Fine-quality pads of 1 to 3 cts. may cost $1,000 to $2,000 per carat. Blue star sapphires of 5 to 10 cts., with little or no gray and a fine-quality star, should cost $1,000 to $2,000 per carat. Black star sapphires, meanwhile, are fairly inexpensive at $10 to $15 per carat. Diffusion-treated sapphires should cost about $100 to $200 per carat.

Astrological gems. For those born between Aug. 22 and Sept. 22 (Virgo), the astrological birthstone is carnelian, the orange-colored chalcedony. Those born between Sept. 22 and Oct. 22 (Libra) can claim peridot as their astrological gem.

A final note: While some months have alternative birthstones, sapphire is the sole birthstone for September.