Questions About Emeralds

Emeralds are a treasure from the earth valued for centuries.

Consider the emerald, a variety of beryl colored green by vanadium or by chromium and long valued by people across the world. Whether you are considering buying an emerald, making a focused study of gemstones or just curious, gazing at this beautiful stone calls to mind questions on its history, value and cultural meaning.

What Are the Treatments Done to Emeralds?

In the gem world, the process of oiling emeralds is an accepted treatment. Oiling is a centuries-old process, involving submerging emeralds in oil, today commonly cedar oil. The oil fills in fissures in the emerald, improving its clarity, and can help further prevent cracking. However, colored oil is not acceptable, and this particular treatment must be disclosed in the emerald's treatment report. Another accepted treatment is the process of filling fissures with resin, which is somewhat more permanent than oiling.

Are There Synthetic Emeralds?

Synthetic emeralds are commercially available, and are also referred to as "created emerald." The process for creating synthetic emeralds requires taking a seed crystal, a beryl. Emerald synthesizers rotate the seed crystal, placing it in contact with a melted flux of vanadates, tungstate and molybdates. The crystal is removed and the emerald forms over the beryl seed crystal. Synthetic emeralds tend to possess feathery inclusions.

Where Does the Name Emerald Come From?

The modern name emerald originates from the Greek word "smaragdos". This word, which means "green gemstone," entered into Old French, and eventually English.

How Long Have People Mined Emeralds?

The mining of emeralds extends as far back as 5000 years. Egyptian pharaohs mined a now exhausted emerald deposit near the Red Sea, between 3000 and 1500 B.C. Emeralds are also mentioned in the Vedas, ancient texts from India, in which they were stated to have magical properties. Emeralds were valued by the ancient Aztecs and the Incas.

How Are Emeralds Mined?

Commercial emerald mining today is done by strip mining (sometimes also called open-cut mining or opencast mining). Strip mining involves digging into the ground, creating a pit, and removing the unwanted rock and soil from the dig site.

Where Are Emeralds Mined?

Sources of emerald include Brazil, Madagascar, Zambia, Russia, India, Zimbabwe, Pakistan, Colombia, the United States and Afghanistan. Of all the sources in the world, Colombia produces the top natural emeralds in the market today. Emeralds from Colombia are the only emeralds that do not have a slight hint of blue in their coloration.

However, Brazil has deposits of emeralds with six-sided stars, called cat's eye emerald. This type of emerald is incredibly rare.

How Do Emeralds Form?

Emeralds form in hydrothermal veins, in a metamorphic (involving heat and pressure, but not enough to melt) environment, and in pegmatite deposits. In the hydrothermal vein formation process, fluid with all the necessary components of emerald flows into a natural cavity and the heat and pressure form emeralds.

In pegmatite deposits, magma containing the fluid with the elements necessary to form emeralds cools down, leaving emeralds.

In these formation situations, temperatures range from 932 to 1112 degrees Fahrenheit, with around 10,153,000 to 20,305,000 pounds of pressure for every square inch. Calcite, feldspar and quartz tend to form in relation to emerald.

How Do I Clean and Care for an Emerald?

Ultrasonic cleaners or strong soap are not considered safe, and neither is submerging an emerald to clean it. Gentle rubbing with a damp cloth is recommended for cleaning the surface of emeralds.

You should not leave an emerald near a heat source or wear it while washing your hands or cleaning the house.

What Makes an Emerald Valuable?

Size, clarity, intensity of color and treatments are all evaluated in valuing an emerald. Larger and clearer emeralds with a bright green color are considered valuable. Other hues of color may be noticeable and an emerald will still be valuable.

Imperfections such as cracks and inclusions are normal in emeralds, and are called jardin. Gemologists use jardin to help prove if an emerald is a natural emerald.

A Colombian emerald with proper intense coloration, big enough size and considered to be flawless can exceed a diamond in value.

References

• Gemological Institute of America: Emerald
• "Synthetic, Imitation & Treated Gemstones"; Michael O'Donoghue"; 1997
• "Secrets of the Gem Trade"; Richard W. Wise; 2003
• Emporia State University: Earth Science: GO 340 Gemstones & Gemology: Beryl: Emerald
• "Gemmology"; Peter G. Read; 2005
• University of California at Berkley: Department of Earth & Planetary Science: Where Do Gems Form? & Where Are They Found?

Resources

• International Colored Gemstone Association: Emerald
• Federal Trade Commission: Guides for the Jewelry, Precious Metals, and Pewter Industries
• Great Mining: Open-Pit Mining
• "Crystals"; Jennie Harding; 2007
• "Firefly Guide to Gems"; Cally Oldershaw; 2009
• "Mining in the Americas: Stories and History"; Helmut Waszkis; 1993