The beryl family includes some of the most popular and expensive gemstones. Emerald and aquamarine are well-known and popular choices for jewelry, while red beryl is one of the rarest and most expensive gems. Beryls can range from colorless to black, and crystals can range in size from single carats to extremely large and flawless examples displayed in museums.
Beryl consists of the elements beryllium, aluminum, silicon, and oxygen. Normally colorless, beryls take on colors from a variety of trace elements such as chromium and iron. Although beryllium is one of the rarest elements in the earth, beryl gemstones are fairly common. Many types of beryl make excellent jewelry stones and can take an exceptional polish. A well-finished beryl will often appear to have a much higher refractive index.
Blue to blue-green aquamarine is a traditional favorite. In the past, the pure blues were preferred to those that were slightly green, so aquamarines were routinely heated to remove the green color. However, there is a growing demand for natural, untreated, blue-green aquamarine.
Heliodor is the golden variety of beryl, ranging from a pastel yellow to a rich gold, or sometimes a slightly greenish, yellow.
Emerald is acknowledged as one of the most desirable gemstones. Emerald’s green color comes from traces of chromium, vanadium, or a combination of both. Any green beryl that does not have the purity or saturation of color is simply a green beryl. (Editor’s note: some gemologists strictly define emeralds as those beryls colored green by chromium).
Red beryl, or bixbite, is exceptionally rare. The only place this raspberry to deep rose red stone is found in gem quality is the Wah Wah Mountains of Utah. Faceted gems rarely exceed two carats and are usually included.
Morganite is the pink beryl. While it is often a pure pink, top values go to the salmon/peach shades. Morganite is never dark, with a maximum tone of three.
Goshenite is colorless beryl and very common. There is little demand for this variety, so prices are always low. The same can be said for yellow beryls, though there is more demand for stones over 10-15 carats. Green and olive-colored beryls (those not considered emeralds) are not well known to the gem buying public.
Cat’s eye, star, and shiller effects in beryls are strange curiosities. Cat’s eye aquamarines and emeralds are sometimes rather large. Oriented ilmenite inclusions in pale green aquamarine from Governador Valadares, Brazil, create a brown body color and cause a schiller effect or sheen. When such an aquamarine is carved into a cabochon, a star effect is created. Black star beryls have no fluorescence or distinctive absorption spectrum and are often confused with the latter.
All beryl varieties may have inclusions. Emerald, however, is almost always included, and its list of possible inclusions is extensive. Its inclusions can even help identify where it was mined. See the emerald encyclopedia entry for more details.
All colors of beryl can be produced by the hydrothermal method, and emeralds are also flux grown. Caution must be exercised when identifying these gems, as it is easy to mistake naturals and synthetics. However, synthetic production can create peculiar inclusions that can help distinguishing synthetic from natural beryls.
Beryls are found worldwide. Detailed locations are listed for each beryl variety in its individual encyclopedia entry.
In the United States, goshenite is found in California, Maine, South Dakota, Utah, Colorado, North Carolina, Connecticut, Idaho, and New Hampshire. It’s also found in Canada, Mexico, Brazil, and Russia.
Beryl crystals weighing many tons have been found in pegmatites but these are never gem quality. Aquamarines and green beryls, however, may be completely transparent and still be very large. A crystal weighing 243 pounds was found in Brazil in 1910 that was completely transparent. Another found in 1956 weighed about 135 pounds. Some very large gems have been cut from this type of material. Morganites are usually smaller, up to about 6 inches in diameter. Emeralds are notorious for growing extremely large. Red beryl occurs in crystals up to about 2 inches in length, and these are seldom transparent, even in small areas. The very few stones known are less than 3 carats.
Many famous, large, and noteworthy beryls are displayed in museums around the world. Detailed listings can be found in the individual encyclopedia entries for each beryl variety.
Included gemstones like most beryls should be cleaned with mild detergent and warm water. Emeralds should never be cleaned in mechanical systems.
From International Gem Society