Understanding Gem Jewelry

Emerald, May's birthstone, is among the most revered and expensive of all gemstones. It has long since been regarded as the quintessential green in nature. Pliny the Elder wrote of emerald, about 50 A.D: "Nothing greens greener." The name emerald is derived from the Latin word for green, smaragdus. Its typical color is a beautiful, distinctive hue known, in fact, as emerald green. But emerald can also be light or dark green, bright green or leaf green.

Emerald belongs to the beryl family, which is a crystal structure composed of aluminum and beryllium. Other beryl siblings are aquamarine (blue, blue-green) morganite (pink, peach), goshenite (white) and helidor (yellow, gold). The vivid green color of emerald is attributed to a replacement of aluminum with chromium in the structure of beryl. There are, however, green beryls that are not emerald because they do not contain chromium.

On the Mohs scale of hardness, emerald ranks 7.5-8. While it is a hard stone (harder than quartz and slightly less hard ruby and sapphire), emerald is fairly brittle. This is largely due to inclusions inherent in the material, along which the emerald can split if exposed to sharp impact.

Today, most natural gem-quality emeralds are produced in Colombia, Brazil and Zambia. Emerald is also found in Zimbabwe, Tanzania, Madagascar, South Africa, Australia, Russia and the United States (North Carolina). In fact, it has a rich history dating back 4,000 years to ancient Egypt. Cleopatra was famous for wearing lots of emeralds. Colombian emeralds have long held the reputation as being the best, but Brazil, the world's largest producer, has recently narrowed the gap in fine quality.

Recently, emeralds have been grown in the laboratory, and have begun to appear on the market, arousing some controversy. Scientifically speaking, laboratory emeralds are essentially identical to natural ones in color, hardness, brilliance, and even inclusions. Only a gemologist can distinguish between the two, which may be the source of the controversy: The industry knows the difference, but the consumer does not.

Clean emeralds with a soft, damp cloth, warm water and a soft brush. Do not use mechanical cleaners. Avoid chemicals and heat that may dissolve oils used during cutting and processing to conceal inclusions. Have a jeweler re-oil your emerald every few years. Although emerald is harder than quartz, its crystal structure makes it brittle. Avoid impacts. It is important to buy fine emerald from a reputable retailer who will provide, in writing, all pertinent information regarding the gem including enhancements and special care notes.

Gemstone colors

Emerald - The greenest of the green, emeralds were cherished by the Romans above all other gems. Find out what makes this favorite of Cleopatra's so unique

Garnet - January's birthstone is famous for being as red as a ruby, but this colorful gem actually comes in every color but blue. Discover this elusive chameleon

Opal - Opals are the gem world's silvery mirrors, reflecting back every color in a flash of pastels or a streak of fire. Uncover this enchanting stone.

Peridot - Peridot is a gem that gets around. From ancient Egypt to present-day Apache mesas, even in space meteorites--you never know where its green gleam is going to show up.

Ruby - The color of courage and blood, rubies are even more precious per carat than diamonds. See why the Biblical authors to modern collectors use them as the measure of ultimate value.

Tanzanite- Millions of years in the making, deep-violet tanzanite revealed itself to humans only thirty years ago. Read about this newest discovery.

Sapphire - Blue as the perfect sky, sapphires have been used as protective talismans for centuries. Learn about the versatility of this stone that combines hardness and color variation like no other.

Tourmaline - Available in every color and saturation, this tough crystal has become a popular substitute for rubies, emeralds, and sapphires. Unmask this clever chameleon.

Turquoise - The lovely opaque blue of turquoise is produced by traces of copper in the stone. Elements of iron will also create a pretty, pronounced green hue. Oxides contribute to the stone's famous gray, brown or black veining.