Nothing says green like the emerald. The most precious stone in the beryl mineral group, emeralds get their distinct green coloring from the presence of chromium and sometimes vanadium in the crystal. Ranging in color from bluish green to greenish blue, emeralds can display a depth of color that few gems can match. They are the most highly prized of all green gemstones.
With a history spanning thousands of years, from ancient Egypt to the present day popularity of emeralds from Colombia, emeralds have been consistently counted among the “big three” of colored gems, along with rubies and sapphires.
Basic Emerald Gemology
Not surprisingly, the name emerald comes from the old French word ‘esmeralde,’ which is derived from the Greek word for ‘green stone.’ By definition, an emerald is any medium to dark green beryl colored by chromium; the presence of vanadium or iron makes the gem simply ‘green beryl.’ This definition has become problematic, as the American jewelry industry changed the definition of emerald to include vanadium colored beryl in the 1960s. In Europe and the United Kingdom, vanadium colored beryl is still known as ‘green beryl.’
Like all colored gemstones, emeralds are graded using the classic 4Cs one uses to evaluate diamonds—color, cut, clarity and carat. While color is the most important criteria, clarity ranks a close second. To be considered a top quality gemstone, an emerald must have not only a pure verdant green hue, but also a high degree of transparency.
Emeralds are almost as famous for their inclusions as they are for their color. These inclusions are often visible to the naked eye, and as a result, emeralds are usually graded by eye rather than under the standard 10x loupe used to grade diamonds. While an ‘eye clean’ emerald might be considered to be ‘flawless,’ the constellation of inclusions found in most emeralds is known in the industry as the ‘jardin,’ the French word for garden. An emerald’s ‘jardin’ can be so unique that it can be used by jewelers to determine a stone’s origin, or even identify a particular stone.
Because emeralds have more inclusions than most gems, with fissures often breaking the surface, they are notoriously fragile, even though they are fairly hard at 7.5-8 on the Mohs gem hardness scale (diamonds score a 10 out of 10). While their hardness makes them less vulnerable to surface scratches, they can easily be chipped or broken.
Emeralds are used in many varieties of jewelry, though because of their fragile nature, they are often better suited for use in necklaces and pendants rather than rings. Emeralds are often cut in the so-called ‘emerald cut’—a step or trap cut featuring a rectangular or square shape with truncated corners. This cut was specifically developed for emeralds to maximize the stone’s color while protecting it from mechanical strain and internal stress. Emeralds can be cut into other shapes, including oval, round, and pear. Emeralds of lower quality are often cut en cabochon.
Treatments for Emeralds
Because of the numerous inclusions in most emeralds, almost all are treated to minimize the appearance of these internal fissures. The industry standard is to use cedar oil to fill and obscure the fractures. Cedar oil has similar optical properties to the emerald itself, so that light passing through the stone is not distorted in a way that detracts from the emerald’s natural color, saturation, and hue. The practice of treating emeralds with cedar oil is an accepted practice within the industry, and is considered a semi-permanent treatment. All emeralds should be considered oil treated unless otherwise specified. A certified unoiled emerald with great clarity commands the highest of premiums.
Other forms of emerald treatments to increase the stone’s durability include the use of resins, glass, and plastic polymers that are melted into the gem. The color of emeralds is sometimes enhanced with the use of tinted oils and polymers. These kinds of treatments are not industry standard, and are considered by most gemologists to be a deceptive practice.
History of Emeralds and Famous Emerald Jewelry
The first emeralds known to historians are from ancient Egypt, mined as early as 2000 B.C.E. The green gem was thought to be a representation of spring, and came to symbolize fertility and rebirth. Mummies were sometimes buried with emeralds to ensure eternal youth in the afterlife. An emerald source found near Cairo (today known as the Cleopatra Mine) would continue to be the main source for emeralds until the Middle Ages.
During the Roman Empire, emeralds were thought to reduce stress, promote mental clarity, and ward off evil spirits. Widely reported legend has it that Emperor Nero watched the gladiator fights through a remarkably transparent emerald because he found the green color calming. Ancient Romans even believed that the very soul of an individual was restored when they wore emerald jewelry.
When Cortez and the Spanish Conquistadors ravaged South America, they found Incan and Aztec sources of emeralds that would satisfy European demand for hundreds of years. The best emerald mine was in Muzo, Colombia, and it still produces some of the finest quality emeralds today. When the Spanish forced the native population from the mine, the gems they sent back to the Old World were made into precious jewelry pieces for the monarchs and ruling classes of Europe, India, Persia, and Turkey.
India also has a long and rich history of treasuring precious gems, and their reverence for emeralds is well documented. The famous Moghul Emerald dates from 1695, and was thought to have been originally mined in Colombia. The 217.8 carat gem is carved with a Shi’a prayer on one side and a rosette surrounded by poppies on the other. It sold at auction in 2001 for a phenomenal 2.2 million dollars.
Another famous emerald, the Chalk Emerald, was thought to have belonged to the Maharani of Boroda, India. This Colombian emerald was famously recut to 38.4 carats by Harry Winston, and set into a ring surrounded by 60 pear shaped diamonds. It now resides at the Smithsonian National Museum of History.
How to Sell Your Emerald Jewelry
When it comes to selling previously-owned emerald jewelry, Diamond Estate Jewelry Buyers is widely recognized as the best place to sell high-quality emerald and diamond rings, earrings, and necklaces. To learn more about why we have earned that reputation, please go to our article: How to Sell & Auction Emerald Jewelry.
You can also contact us today for a free consultation and appraisal of your valuable emerald jewelry.