How Are Emeralds Processed?
Emeralds are one of the rarest and most valuable gems in the world. Throughout history, they have been worshipped by the Incas, favored as decorations by the Egyptians and used to promote healing and good luck by the Indians. Now, emeralds are prized stones to set in jewelry, while still thought to bring wisdom, spiritual growth, love and devotion. Their natural flaws make them difficult to cut, but highly valuable after skilled and gentle processing. Does this Spark an idea?
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Formation
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Raw emeralds are a kind of beryl, a mineral composed of beryllium, aluminium, oxygen and silicon. Colorless beryl crystals are fairly common, but occasionally chronium atoms replace the aluminium atoms in the beryl crystals, producing an emerald green hue. Because chromium is found in different parts of the earth's crust than beryllium, the chance of this happening is very rare. It takes a tectonic process such as metamorphism or emergences and erosion of land for these contrasting elements to find each other and crystallize to form emeralds. Although all emeralds are green, a stone's brilliance depends on where it was formed. Some of the most valuable stones are mined in Columbia, famed for its bright green gems with a tinge of blue. Brazil, Columbia, Zambia, Pakistan and Zimbabwe produce beautiful emeralds too.
Sawing and Cutting
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A skilled gem cutter will examine a raw emerald and analyse its flaws to decide which shape will enhance its value. Its final shape should bring out its color and disguise natural cracks. The aptly named emerald cut was devised especially for this gem and is a popular choice, giving a rectangular or square face and bevelled corners to protect it from accidental damage. A cutter's skill can alter the emerald's vibrancy, darkening the green by cutting a small table surface and many smaller ones around the sides. A larger surface will lighten it. Emeralds are highly prized so cutters take great care not to damage the naturally soft stone, cutting it into small pieces first to make the final shaping easier.
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Color Enhancing
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Few emeralds escape color enhancement but those which do can be more valuable than diamonds. To enhance their color, emeralds are usually immersed in a colorless liquid such as oil or paraffin, which penetrates fissures and cracks in the emerald and fills them in. Assume an emerald has been through this treatment, unless it has a laboratory report stating otherwise.
Choosing an Emerald
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The best emeralds boast a deep color, are free of cracks and cleanly cut, and these stones are very expensive. When choosing your own, make color quality your priority, then consider clarity, cut and carat weight. The most valuable stones are usually dark and rich, but also a fine green, without cloudy imperfections. For high clarity, an emerald should have few natural inclusions. An ideal cut leaves a symmetrical gem with smaller surfaces, or facets, around the sides to enhance the color. Carat weight should be your last consideration, because a large, cloudy, poorly-cut emerald will usually be less valuable than a brilliant smaller gem. Ask your jeweler for a certificate of authenticity.
Future Care
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While color enhancing treatment brings out an emerald's green glow, it also makes it too fragile for harsh cleaning. A treated emerald should never be put in an ultrasonic cleaner, as the enhancers will escape the stone's fissures, softening it and revealing its natural flaws. Instead, wash your emerald with warm soapy water and gently brush with an old toothbrush. Rinse well and pat with a dry cloth.
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References
Resources
- Photo Credit emerald image by Barcabloo from Fotolia.com
