So, you’ve never heard of the “big four”? This isn’t, as you might think, the front line of a championship football team. Instead, it’s the familiar “big three” – ruby, emerald, sapphire – but with something added. That something is tanzanite.

The traditional big three can trace their history back to ancient civilizations, while tanzanite dates only from 1969. Yet, no gem has ever gained acceptance as rapidly as tanzanite has. In less than 30 years, this gem has grown from collectors’ stone status to its new-found fame.

Early critics thought tanzanite didn’t stand a chance as a jewelry stone, mainly because it was too soft. Over time, however, jewelers and bench people have learned the proper care and setting of tanzanite. That has allowed its beauty to propel tanzanite to best-seller status.

How price = popularity. Tanzanite started its climb in the early 1980s. Dealers were buying more heavily at trade shows and retailers were having more success selling this beautiful gem. But no one expected the boom soon to come.

Tanzanite prices peaked in 1984. Popularity had pushed wholesale prices for extra fine goods as high as $1,000 per carat, though the average for extra fine was about $750 a carat. Seeing an opportunity to sell more tanzanite, miners in Tanzania flocked to the area and chaos resulted. Supply outstripped demand and, as a result, prices dropped. The slide continued over the next few years, hitting bottom in 1993 at an astonishingly low $200 per carat. Since then, prices have rebounded slowly. Today, an extra fine one-carat tanzanite sells for an average of about $250.

The big drop in prices hurt dealers at first. Many were stuck with very high priced inventories which they had to sell at a loss or hold in hopes of a rebound. Those who stuck with tanzanite, however, soon forgot about the losses. Low price made tanzanite one of the hottest gemstones of the ’90s. Home shopping networks – which probably would have shown little interest if prices had stayed high – began marketing tanzanite. So did large catalog stores. Consumer awareness skyrocketed and soon every jeweler carried tanzanite as a staple item.

Fortunately, supply has kept up with demand. Prices have risen about 10% during the last year and the market seems to be in equilibrium.

Beware of imitations. To date there are no tanzanite synthetics on the market. But someone probably is in a laboratory right now trying to create one, because tanzanite is such a popular gemstone. If there is great demand for a natural gemstone, there often is considerable demand for its synthetic counterpart.

Remember, however, that a synthetic is a man-made gemstone with the same physical, chemical and optical properties as a natural gemstone. While no synthetic tanzanite yet exists, there are many imitations. These can be confusing. The following compilation of imitations and their properties should help you sort them out.

The first imitations on the market were synthetic corundums with a variety of trade names. The Allanite Co. (now known as the Lannyte Co.) first marketed its simulant as “coranite” in 1992 and registered to trademark that name in June 1995. Coranite is a blue synthetic corundum; since the company couldn’t manufacture a purple corundum variety, it turned to YAG. Initially, it marketed the YAG tanzanite simulant under the coranite name as well.

Gemstones International also marketed a simulant, called “cortanite.” It registered to trademark this name in February 1996, but opposition was filed on the grounds that the name cortanite was too close to coranite. Gemstones International later agreed to change the name of its product to “chortanite.” Lannyte Co. also decided to rename its purple simulant since it was not a synthetic corundum; it settled on the name “tanavyte.”

U & M Science Co. manufactures another imitation tanzanite under the trade name “tanzani,” which is sold by M.P. Gem. This synthesized polysilicate has an RI much closer to natural tanzanite’s, so it is a convincing simulant. A price of $5 per carat makes it an affordable alternative to the real thing.

It is difficult to separate natural tanzanite from some imitations by eye alone. However, those owning a refractometer should find separation fairly easy, since none of the imitations will give the same refractive index as tanzanite (1.691-1.700). The RI of the simulant from M.P. Gem is close, at 1.66-1.67, but is singly refractive while genuine tanzanite is doubly refractive. Sometimes the doubling of facet junctions may be seen on the pavilion when looking through the table of the stone (see photo at left).

Magnification can be helpful when the setting prohibits an accurate RI reading. Simulants composed of synthetic corundum may exhibit curved striae. GIA classifies tanzanite as a Type I gemstone, so don’t expect to see much in the way of inclusions. Graphite inclusions may be present; hematite in hexagonal crystallization also may be found and may show red internal reflections and metallic luster.

Buying tips. Tanzanite is still a gem to buy. Tom Moriarty of Aaland Gems, Merrillville, Ind., says he sold more tanzanite than all other gems combined last fall. Prices remain reasonable at only about $250 a carat for extra fine qualities, but are rebounding slowly. Many dealers expect tanzanite’s success to continue for many years to come. Knowing that, jewelers might be wise to stock up on this gem.

Here is what to look for. The color of tanzanite may range from a purple to a blue. The ultimate color depends partly on how the stone is oriented when cut; the same material may exhibit a blue, a purple or a combination of purplish blue or bluish purple. At first, blue always commanded a higher price, since it most closely resembled sapphire. But every consumer prefers a different color, so don’t oversell the blue.

Saturation is the key to a fine color. In lower grades, tanzanite may be less saturated and may also have some gray.

Tanzanite is available in a variety of shapes. There are pleasing ovals, emerald cuts and, occasionally, rounds. The most popular shape may be the trillion. Large single stones often are purchased for rings and pendants. In smaller sizes, matched trillions are very popular.

Above one carat, shape generally has little effect on the price, but special designer cuts will carry a premium. So may trillions below one carat. Matching is a special consideration with trillions, which are very popular for use as accent stones around a center of a different color (pink tourmaline, perhaps?). When pricing matched trillions, do not be surprised to pay as much as 30% more for an attractive pair.

Mellow melee. The color saturation of small tanzanites, especially melee, tends to “wash out,” although there is no distinct cutoff point at which material will start to lighten. Stones less than one carat probably will be less saturated; under a half carat, forget about finding saturated stones. (See above.)

This is important to remember when buying, selling and grading. The classic definition of “extra fine” changes when you’re referring to tanzanite melee. Downgrading a small stone that is slightly less saturated in color is unfair. Instead, look at other attributes, especially its brightness and cut. Precision-cut, well-matched and calibrated tanzanite will cost more.

As a buyer, don’t be too picky or you’ll come away empty-handed. As a seller, when showing tanzanite, be sure to explain that lighter colors may be necessary in small stones so a customer doesn’t expect to match that five-carat gem she already owns. Appraisers also should remember to be less critical of color when grading small stones.

Care. The hardness of tanzanite is 6-7, which is a bit soft. It definitely is dangerous to put tanzanite in an ultrasonic cleaner. I recently visited a local jeweler and was aghast to see him removing a tanzanite from his ultrasonic cleaner. I quickly examined the stone and sighed in relief to find it was undamaged. I told him about a setter who had to replace two tanzanites within a few days for a jeweler. At first he thought that he had fractured the stones during setting. When he called me for an explanation, I warned of the delicate setting process but also asked how he had cleaned the stones after setting. Sure enough, he had placed them in the ultrasonic cleaner and fractured the stones internally.

Steaming also is not recommended. Tanzanite should be handled with care much as is an oiled emerald. Make setting the last step, after the mounting is thoroughly polished. Then, simply wash the finished jewelry item in a solution of warm water and jewelry cleaner.

When handled properly, tanzanites do not pose any real problems and can be worn for many years without incident. Treat them with the same care you would give to a fine emerald or a strand of cultured pearls.

References: Gubelin, E.J., Koivula, J.I., (1986), Photoatlas of Inclusions in Gemstones, ABC Edition, Zurich, Switzerland.

Richard Drucker is president of Gemworld International and publisher of The Guide, a pricing publication he began in 1982. It is used worldwide for prices of colored stones and diamonds. He is an international gemstone consultant and currently lectures and conducts seminars. He has published numerous books in the jewelry industry. His company can be reached at (888) GEMGUIDE or (847) 564-0555.