Although the beryl family is full of wonderful colors, in its purest state beryl is colorless. Colorless beryl actually has a varietal name, but unless you’re a collector of unusual gems, you probably haven’t heard of goshenite. (And you’ll want to remember this variety later when we talk about enhancements.) There are, of course, colored beryls that you will recognize by their variety. The most recognizable is saturated green beryl—better known as emerald. There’s the blue-green/green-blue beryl, aquamarine, and a pink or peachy-colored beryl called morganite. But if you were to ask what yellow-colored stones are most popular, beryl would not be on the list. Topaz usually comes to mind first, followed closely by citrine quartz (both of which can be considered for the birthstone of November, although topaz is the more traditional gem). Certainly there are fancy yellow diamonds, but most people don’t consider diamond a member of the colored stone genre. This split probably comes from the lapidary who either specializes in gems of hardness 9 or below, or solely in diamond, which has a hardness of 10. With this in mind, don’t overlook beryl for your yellow-gems showcase. It’s a real beauty that can cover a wide range of price points.
History and romance. Yellow beryls have been mined for centuries, possibly as far back as 1600, but the name heliodor (“gift of the sun”) was given to this fine golden beryl after its discovery in a deposit near the town of Rössing, Namibia, simply to give it some notoriety in the local press. The most important sources of yellow beryl, which is often found with aquamarines, are in Brazil and Ukraine, although there are still good deposits of the gem in Namibia as well as new deposits in Tajikistan, Zimbabwe, and Madagascar.
The largest faceted flawless yellow beryl in existence is located at the Smithsonian’s National Gem Collection. A Brazilian stone, it weighs 2,054 cts. and measures more than 4 inches in length.
Qualities. Yellow beryls are expected to be quite clean, like aquamarines. However, the material from Madagascar, while it has a rich natural color, also shows a lot of inclusions.
Color variations. The yellow beryl color range is wide, from the greenish-yellows of Ukraine to more typically Brazilian pure yellows to slight brownish/golden-colored yellows and reaching the other end of the spectrum with truly brownish-yellow hues. Also from Brazil are rare orangey-yellow beryls.
Given this wide range of color, there are mixed reactions to the use of the name “heliodor.” “In my opinion, the term ‘heliodor’ should probably be used only with the pure yellow beryl,” says Richard Homer of Gems by Design in Kent, Ohio.
Josh Hall of Pala International in Fallbrook, Calif., notes that any of the beryls that have a yellow primary hue are typically called heliodor. “Pastel or deep color, greenish and orangey, they all coincide with the literature,” says Hall. But today, everybody wants to be politically correct. Hall notes that suppliers now use a color description rather than an older term like heliodor. “We just try and make for better communication. ‘Heliodor’ has a nice ring to it, but it doesn’t accurately describe the true color of the stone,” he says.
Most yellow beryl material is cut in large sizes because of its weak saturated color. The larger the stone, the more color is shown. “It’s really ideal material for concave faceting,” says Homer. “Beryl is clean, crisp, and wonderful.”
“In nature, it’s difficult to find pure yellow,” explains Hall. “There’s pure yellow in sapphire, and occasionally in a citrine, which is why there’s a premium when you have a pure color.” Homer also notes that the natural beryl color is usually too light; if the color is obvious, than the stone is probably too expensive.
Enhancement. Natural enhancements include the “acid etching” of the rough crystal, as seen in those pictured from Ukraine. “I started this kind of cutting in 1984, and I was thinking of not disturbing the nature,” says Fritz Wilshaus, master gem cutter with Philipp Becker in Idar-Oberstein, Germany. Another enhancement that’s considered natural is the color that results from the proximity of heliodor deposits to radioactive mineral deposits—for example, Rio Tinto’s uranium mine in Rössing, Namibia.
Many of the bright yellow or slightly brownish “golden” beryls have been irradiated. Just a short burst of gamma or electron beam irradiation is enough to color goshenite. According to Tom Schneider, irradiation expert and colored gem importer in San Diego, the accidental discovery of irradiated beryl came while irradiating colorless topaz. As the topaz was slowly turning blue, the goshenite—which had been accidentally mixed in with the topaz—was quickly turning bright yellow.
Different mines yield different material, notes Schneider—even though it may all look like the same goshenite, it can contain different trace elements that react uniquely to the irradiation process. Some irradiated beryls become a bright lemony yellow, while others become a more golden color. According to Schneider, golden beryl is much more salable and attractive.
On rare occasion, irradiation produces pink morganite. While irradiation-processed color is stable, Schneider does try to “bleach” the stones in the San Diego sun to test for fading.
Pricing. Fine natural-color yellow/golden/heliodor beryl prices are consistent with the complete range of yellow colors, with the strong saturated golden-colored gems commanding slightly higher prices. For stones weighing between 5 and 10 cts., prices range from $40 to $55 per carat. Specialty cuts are priced according to the artistry of the lapidary. Irradiated heliodor is fairly inexpensive—even the concave faceted stones are priced at just $30 per carat. But don’t let the low cost per carat lull you into thinking you can own a $30 concave faceted gem—most faceted irradiated heliodors weigh between 5 and 15 cts.
Care and cleaning. Use standard precautions when wearing this colored gem. Although its hardness allows for some fairly heavy abuse, and it can resist chipping, don’t throw it into the jewelry box with sapphires, rubies, or diamonds, because they will easily scratch golden beryl.
Bench repair and setting. Even though the natural color should have no reaction to heat, it is best to remove or protect the gem from heat while performing jewelry repairs. Irradiated gems will change color if heat is directly applied, so if you are uncertain of the color origin, take precautions.
Recommended reading. For more information, see:
Gemstones, Symbols of Beauty and Power by Dr. Eduard Gübelin and Franz-Xaver Erni (Geoscience Press, Tucson, Ariz., 2000).
Emerald and Other Beryls by John Sinkankas (Chilton Book Co., 1981).