Tucson’s gem and mineral shows are the most important loose colored gemstone shows in the world. For a week or two in early February, the city boasts the widest variety of gemstones and gem-related information available anywhere in the world.

What started as an event sponsored by a local gem and mineral club back in the ’50s, has grown into 18 different shows in 24 different locations around town. Three of special interest to jewelers are clustered together: the American Gem Trade Association show at the Convention Center, the Gem and Lapidary Dealers Association show at the Holiday Inn and the Gem and Jewelry Exchange event in the big tent across the street.

This year’s visit to the gem mecca showed that popular gemstones are changing and that the enhancement issue is more critical and confusing than ever. While piles of gems ranging from almandite to zircon were on hand to tempt you to buy, certain varieties made more of an impact because they were unusual, unique, popular or just incredibly beautiful. Here, in no particular order, is a look at some of them.

Ancient Roman glass. With all the incredible stones on display, I never thought that the first “gem” to catch my eye would be glass.

Jackie Cohen, designer and jewelry artist for Roman Glass Jewelry, was tucked back in the Designer Pavilion of the AGTA show. He has assembled a fine collection of 18k yellow gold earrings, pins, necklaces and bracelets featuring broken shards of ancient Roman glass retrieved from archeological digs. This 2,000-year old material resembles some of the finest Lightning Ridge opal I’ve ever seen. Indeed, its iridescence stopped me in my tracks as I raced by, and while I was standing there, a half dozen jewelers stopped to ask what the opal jewelry was selling for.

When this ancient glass was produced, certain minerals native to the area were incorporated into the melt. The aging of these elements over time has given the glass its opal-like appearance with differing patterns of iridescent colors – some circular, some curved, some straight – on backgrounds ranging from white to dark blue.

While the glass is not necessarily fragile, it is old and, says Cohen, should be handled somewhat like pearls. Almost anything other than a soft cloth could potentially damage the iridescence.

Cohen has been producing ancient Roman glass jewelry for almost two decades – first in Israel and now in Tarzana, Calif. Each piece is different. It’s art. It’s jewelry. And it’s glass.

Plique à jour. Staying with glass for the moment, try adding some plique à jour enamel work to your inventory. This intricate enameling provides a stained glass effect. Art Nouveau 1910, a company of fourth-generation jewelers and artists from Barcelona, Spain, had quite a few onlookers at its display of necklaces and pins in the GJX tent. The 18k yellow gold designs resembled some from the turn of the century. The craftsmanship was very good, with the pieces finished nicely even on the reverse. Wearing plique à jour jewelry against a pastel colored blouse or jacket brings out the see-through effect and shows off the subtle colors of the enamel.

Spessartite garnet has become very popular within the last year because of its price, availability and, most importantly, its bright orange color. There wasn’t any shortage of it in Tucson. Depending on its source, spessartite ranges from very pale, yellowish oranges to a dark saturated orange. The most prevalent sources are Madagascar and Namibia.

G.E.M. Namibia, which owns the “Mandarin Spessartite” mines, had an entire display booth literally glowing orange from the thousands of carats of faceted goods. Namibian garnets differ only slightly in color, from strong to intense orange and yellowish orange. Tom Cushman of Allerton Cushman & Co. and Ya’Akov Almor of Hargem Ltd. were showing the darker, more saturated orange spessartites from Madagascar. These can range from very light orange to medium dark strong to vivid reddish orange. In its efforts to be different, Hargem displayed its spessartite under the name “fireball” garnet.

Chrome diopside. Green also seemed popular. Several dealers were showing Russian chrome diopside. This vivid green gem is gaining notoriety because of its saturated color and extremely reasonable price ($30/ct. average). RCS (Russian Colored Stone Co.) claimed in its sales literature that “chrome diopside will be the world’s leading emerald substitute by the end of the century.” Slowing its growth, however, may be its unromantic name and, perhaps, the fact that there is only one substantial Siberian source.

Demantoid. We’ve reported previously on a new find of Russian demantoid (see March JCK, page 34). More than a few dealers showed this rare gem at the show and it made a big splash. Bill Larsen at Pala International had the most impressive group, with a variety of sizes and colors, from medium yellowish green to strong dark green.

Mexican demantoids resurfaced in response to interest in the Russian material. Charles Vargas at Apache Gems had a nice but small display of Mexican demantoid, along with some andradites which were close, but not quite a demantoid color. Mexican material never achieves the strong saturated green of Russian demantoid, but be aware that the dispersion (“fire”) of this gem disappears as the color becomes too saturated. To get the best bargain, choose the most saturated yellowish green that still has noticeable fire.

Rhodolite. Staying with garnets, rhodolites were shown in good quantity and different colors. Some were almost almandite in color, a brownish purplish red to a very strong purple. Tanzanian rhodolites tend to be quite red, described as a strong saturation, medium dark reddish purple. These would be called “raspberry.” Prices are about $10-$15 a carat.

Oregon sunstone. Carving is one of the more interesting ways to use lesser known gemstones. Angela Conty, a gem carver from Schenectady, N.Y., showed Oregon sunstone carved into rose buds. Hematite platelets in these bronze colored gems create a schiller (metallic-like luster) and spangled effect which is quite striking. Sunstone ranges from a golden to an almost red color. Some even have a strong color change, red to green. Inclusions give it either a sheen, adularescence or aventurescent effect.

Of course, sunstone can be faceted as well. Dust Devil Mining Co., Beaver, Ore., has an excellent collection of both faceted and rough crystals (in case you want to carve or facet your own) with differing colors and inclusion phenomena.

U.S. amethyst. An incredible find of amethyst has occurred right here in the U.S., in Arizona. Mike and Jerry Romanella of Commercial Mineral Co. acquired rights to the production of this mine within the past few months. They say the quality can be quite good.

Material at the front of the tray of goods they were showing – which must have contained a hundred carats of faceted amethyst – appeared very pale and grayish. No wonder most people passed right by their display! But gems in the back rows rivaled any Russian reddish purple amethyst you’ve ever seen. And all of it came from Arizona.

Gold in quartz. Once you’ve held gold in quartz, you’ll feel you’re catching gold fever. The striking metallic luster of the gold appears hypnotizing against the polished white quartz. It wasn’t in great abundance at the show, but showed up in rings, loose slabs and especially in intarsia boxes. It’s getting expensive, with some pieces costing well over $1,000/gram.

This “high grade”material is much more valuable as a specimen than for its gold content. Dawn Fischer of Morning Sun Jewelry notes that “the value of gold bearing quartz varies with each piece.” It all depends on the color of the quartz, the amount of gold and how it is distributed. “The color of the quartz can vary depending on accompanying minerals, but the bright white quartz of the Allegheny District is considered among the most highly prized.”

The most incredible pieces were in some of Nicoli Medvedev’s intarsia boxes. A member of GANA, the Gem Artists of North America, Medvedev is well known for his intarsia and his use of gold in quartz is quite wonderful. His boxes are priced as pieces of fine art.

Black pearls, black pearls, black pearls. They were all over, but only in commercial quality; most black pearls in Tucson were second- and third-run production. Top luster, top color blacks were few and far between. First-run production would be darker, have better luster and show more peacock colors.

No tanzanite shortage. One of the biggest myths is that there is (again?) a shortage of tanzanite. Maybe next year there will be, but it certainly did not happen in Tucson this year. If you couldn’t find just the right tanzanite, millimeter size, blue, purple, heart shape, pear shape, triangle, round, oval, you were in the wrong place. Better quality over-one-carat finished tanzanites ranged anywhere from $275 to $350 per carat.

Amber was in good supply with much coming from Russia. Elizabeth Tarnowska of Morton, Ill., showed the most interesting finished items – white and yellow colored pieces inlaid into modern art forms for pendants and earrings. The Central American amber looked clear with many specimens containing sticks, ants and perfect spiders. The beautiful red Mexican amber from Chiapas was very unusual; most “red amber” I’ve seen has been red plastic. All of the amber was fairly inexpensive. For example, a golfball sized piece of rough with inclusions of sticks and one spider was $20.

Miscellany. I saw some Montana sphalerites of good size and good color … Among its hundreds of gems, Madagascar produces a rainbow feldspar, which was offered faceted at $100-$150 a carat … Vietnamese tourmalines were on display. Some exceptionally pretty medium light pinks – sort of a kunzite color – stood out. Vietnam also produces some fine spinels and peridots … Gideon Gil of Akiva Gil Co. showed quite a nice lot of raspberry rhodolite garnets, a purplish red with a good color shift (creating a slight blue overcast).

If you’re looking for the next tiger’s eye companion, try pietersite. At first, I thought it was an ultra-fine hawk’s eye. The blue could be correct (although they say hawk’s eye never gets that blue), but the fibers to create the typical eye were not oriented properly. They did give the stone quite a sheen, and it would make for some nice and unusual men’s jewelry.

Bill Gangi of Multisensory Arts had one of the most interesting booths at the AGTA fair. Turned alabaster and rosewood bowls, Alaskan fossilized coral (a bone-like material with a beautiful, subtle blue sheen), titanium-coated quartz crystals and even African meteorites were among the unusual items.

In diamonds, Ralph Mueller of Mueller and Associates sees a shortage of 2-carat round brilliant cuts. Even at prices he doesn’t want to pay, he can still find customers to whom he can sell for a profit.

Gems as fine art. The Gemstone Artists of North America (GANA) met one evening to create a more formal group structure. This was their fourth annual meeting and while it proved difficult for artists to agree on “order,” they eventually succeeded.

They also succeeded in promoting their members’ works of gem art at the Gem and Lapidary Wholesalers show. Individual artists also displayed their own work elsewhere and, in addition, many wholesalers who had pre-purchased pieces showed these in their own booths. E.F. Watermellon, for one, displayed a number of pieces by GANA members.

Glenn Lehrer, Peggy Croft, Thomas McPhee, Susan Allen, Nicoli Medvedev, Michael Christie, Gil Roberts, Susan McCune, Amador Braojos and Sherris Cotier Shank all turn gem carving into a fine art. Some of what they do is wearable, some is not. But all is absolutely incredible.

Among other gem carvers of note who displayed at the GLW show were Michael Dyber and Steve Walters. Dyber has created a style called the Dyber Optic Dish, a concave circle which allows you to see deeply into a gem and view his carving on the opposite side. Walters, who carves mostly free form on opaque to translucent gem materials, is typically sold out by day three.

Synthetics – diamonds & others. Chatham Created Gems still is trying to start commercial production. But it did at least display a number of near colorless stones, faceted and rough.

Tairus had a fairly large selection of the “Sumitomo yellow” synthetic diamonds. It now produces a number of Russian hydrothermal synthetics, including sapphire in all colors, alexandrite and aquamarine. Prices for the aqua ($60 a carat) seemed somewhat high compared to natural of the same color and clarity. When asked why, it was stated that Tairus sells its product without reference to the natural gems. Tairus also manufactures synthetic malachite.

Russian Colored Stone Co. also showed synthetic diamonds. Among them were yellows, brownish/orangy yellow, a near colorless round brilliant and a green-yellow “chartreuse” pear shape. These synthetics have the expected identification features. The yellows have hourglass internal graining with a central cloud; the round brilliant has flux-like clouds with metallic crystal-like inclusions. This synthetic diamond was magnetic, being picked up by a $15 neodymium wand.

It takes two to three times longer to produce the colorless and near colorless synthetic diamonds – up to 21 days. Production is currently small and waiting for a manufacturer to request more than 500 crystals per month. A secondary, post-growth process produces the chartreuse color. This involves heat treating cape (very lightly tinted yellow) stones to lighten them. Heat treating fancy yellows also can induce this chartreuse color. The process is permanent.

RCS also carries created alexandrite and red beryl, marketed as “red emerald.”

S & R Rubicon Inc., with offices in Russia and Chicago, distributes Russian synthetic gems in blocks, tubes, rods, flat discs and sheets. It offers sapphire, YAG, citrine, ametrine, amethyst, ruby, rock crystal and a host of “chemical synthetics” (zinc oxide, cubic zirconia, calcium fluoride, etc.) in any size and almost any shape.

Kashan synthetic ruby was displayed at GJX alongside a few other created gems. Steve Ruyle says the synthetic ruby is in its last phase of production. He expects to announce a new synthetic gem to take its place this summer.

U.S. wholesalers complained about the growing number of synthetics, substitutes and glass being slipped into large parcels of natural gems; sellers apparently hope such parcels won’t be checked for authenticity. Starla Turner, Graduate Gemologist for Balzan Gemological Services in San Francisco, identified glass replacements for garnets, topaz and other natural gems in hundreds of pendants made for a major manufacturer. Apparently when the manufacturer’s source ran out of a particular color, it decided to use whatever it could easily find – in this case, glass. A wholesaler in Tucson received a call from a client who had purchased elsewhere a large parcel of smoky quartz; more than half of the 400 carats proved to be glass.

Coatings & enhancements. Coated gems seem to be the latest enhancement fad. I saw everything from the well-advertised Tavolite to what turned out to be coated colorless topaz. A gem dealer from New York described these as diffusion treated, saying how the color enters the top layer of the gem itself. More incorrect information appeared in the firm’s advertising card which promoted, among other gems, “smoky topaz” – which is, of course, a misnomer for smoky quartz.

Lannyte was there, promoting its Coranite and Tanavyte. Both are tanzanite substitutes. Coranite, a synthetic sapphire, contains more blue than purple. Tanavyte, supposedly a synthetic garnet with a hardness of 9 (garnets typically have a hardness of 7 to 7.5), shows more purple than blue.

The Tavolite booth was well stocked with correct information about its product. This is a metallic oxide coating, a chemical deposition, which can be applied to CZ, colorless topaz or other gem materials. The coating bonds to the surface of the gem, turning colorless material into one of strong color.

A desire to learn more about enhancements brought good attendance to seminars on the topic. Richard Drucker of Gemworld International gave a packed house seminar on the wide variety of treatments, while Arthur Groom’s standing-room-only performance dealt with emerald treatments and his Gematrat filler.

At least two emerald wholesalers displayed a questionable passion for disclosure. One had a large sign claiming that none of its emeralds contained oil – because they had Gematrat treatment instead. The second stated that none of its emeralds contained Opticon – because they had been oiled!

Moissanite continued to arouse curiosity, as some wondered whether it would ever be available. Testers to identify moissanite were being marketed before the actual stones made an appearance; Hanneman Gemological Instruments claimed to have one for under $100. (See March JCK, page 35, for tips on how to detect moissanite with just a 10X loupe.)

Congratulations to Alice Keller, who received an AGTA Lifetime Honorary Member award for her dedication to the industry. Keller, editor of Gems & Gemology, has made GIA’s quarterly gemological publication the foremost magazine of its kind in the world.

First Time There? Wear Sneakers!

If you’ve never been to the Tucson gem shows, but plan to attend next year, I would suggest calling for a hotel room today. You may already be too late to get into the major hotels close to the action.

Begin with a short trip of three to five days. Bring very comfortable walking shoes and don’t plan on wearing a tie unless you go to one of the three 5-star restaurants in town. Begin with the three major shows – the AGTA show at the Convention Center, the GLDA show at the Holiday Inn and the GJX event in the big tent across the street. (GLDA may change venues next year to the Doubletree Hotel, long the headquarters hotel for AGTA.)

If you have any shoe leather and energy left after visiting these three, you pick it. There are 18 shows in all, currently in 24 different locations. The easier shows are within walking distance on the other side of Interstate 10 (about 5 minutes from the GJX tent.) The old Pueblo Inn (now called Four Points), the Congress Street Expo and the Days Inn are all right there. If you don’t mind crowds (and crowds signify that something is worth looking at) take the shuttle to the Holidome for the GLW show. The shuttles are free and go to every show. But don’t think for a minute that you’ll be able to see all of them. It’s virtually impossible, unless you are in town for more than a week and have the stamina to do it.