Morganite, heliodor (golden beryl), and goshenite are not widely known to the gem-buying public. Most gem material comes from Brazil, although fine rough has been found in the Malagasay Republic, South West Africa, and San Diego County, California. Gem morganite of superb quality has been mined in Pala, California, along with some of the finest tourmaline crystals known. Morganite was named after the New York banker and gem collector, J.P. Morgan. The name heliodor means “gift of the sun,” which is appropriate for the yellow color. Pale-green beryl, not colored by chromium, is simply termed “green beryl.” An unusual red beryl is found in Utah, but has no gem significance.
The most popular cutting style for emerald and most of the other beryls is a step-cut rectangle with the corners truncated, yielding a characteristic shape known as the emerald cut. Other popular beryl cuts include the cushion cut, a simple rectangle; the hardness of emerald. Because of its typically present inclusions and flaws, emerald is a fragile 71/2-8 on the Mohs scale, which is ample for ringstones.
Occasionally a beryl contains fibrous inclusions, and a cabochon emerald, such as peridot, tourmaline, green zircon, and demantoid, can naked eye even a glass imitation can sometimes be deceptive.
Consumer Tips-Many emeralds on the marker have been treated with oil, typically grape-seep oil. This oil, which may even sometimes be colored green, seeps into fractures in the gems and makes them far less obvious. The oil can usually be detected with ultraviolet light.
Synthetic emeralds are often manufactured with inclusions, to appear more realistic. These inclusions are characteristic of the manufacturing process and can usually be identified by a trained gemologist.
Many synthetic emeralds are currently available, manufactured with various techniques. The prices are substantially lower than those of emeralds of comparable quality, are most synthetics manufactured are of extremely fine color. Some of these are virtually flawless, a condition seldom found in natural emerald. Synthetics may be marketed as “created emerald,” “simulated emerald,” or just “synthetic emerald.”
Major Price factors for emerald are: hue and depth of color, especially the presence or absence of a tinge of yellow (the latter is more desirable); freedom from inclusions and flaws; size; quality of cutting. Large, flawless emeralds are among the scarcest of all gems.
Aquamarines are frequently free of flaws, and the major price consideration is hue and intensity of color; in fine aquamarines absence of inclusions and flaws is taken for granted. Pale-colored stones are quite inexpensive, whereas the price of an aquamarine may soar as the color deepens, especially if there is no tinge of green. Large stones, weighing tens of carats, are available. Synthetic aquamarines are not comer cially manufactured, but several blue gems that strongly resemble aquamarines are available. These include blue topaz and various synthetic imitations, such as blue spinel and glass.
An attractive blue aquamarine may originally have been a yellowish beryl that was heat-treated. The color change is permanent however and there is
No way to prove that the color of a gem is or is not natural. Other artificially produced colors may present a problem, however, as fully discussed on pages 148-149.