May Birthstone Guide: All About Emeralds

Treatments, Synthetics, and Some Folklore

An emerald, a silicate gem
De Agostini Picture Library / Getty Images

Emeralds are green like money, meaning they can get very expensive very fast. With a little education, though, you can prevent yourself from chipping your prized investment. On the off chance you spot a fancy emerald in a flea market, you'll also want to know whether or not it's a fake. Here's some beginner information on the May birthstone to get you started. 

All About Emeralds Chemical Composition and Structure

The May birthstone is a member of the popular beryl family of minerals. Beryl occurs in many other colors with shades dependent on the impurities within the stone. Blue beryl is known as aquamarine. Pink shades of beryl are known as morganite. Yellows are known as yellow beryl and golden beryl. The term bixbite refers to red beryl, a variation that's even rarer than emerald.

Emerald is comprised of beryllium aluminum silicate, translating to the chemical formula Be3Al2SiO6. Prized since ancient times, a fine emerald can be more expensive than a high-quality diamond of the same carat weight. The green color occurs when pure, clear beryl contains trace amounts of either chromium or vanadium.

Emerald hardness ranges from 7.5 to 8 on the Mohs scale. Compare turquoise at 5 to 6 and diamonds, the hardest substance, at 10. Even though emeralds are relatively hard stones, the presence of cracks and inclusions in emeralds can affect their durability. So be careful! A sharp blow to the stone can easily split or chip it. 

History and Folklore

Emerald has been the May birthstone since 1912! It is the traditional gift for the 55th wedding anniversary and can be found all over the world.

Colombian emeralds are among the world's most beautiful, with rich grass-green coloring that's often kissed with a touch of blue. Quality emeralds are also found in India, South Africa, Afghanistan, Pakistan, Russia, and Zimbabwe. Recent finds in North Carolina may provide us with quality emeralds if the mine continues to produce stones.

Egyptian emeralds were introduced to the world about 4,000 years ago, but the stones from those mines are a duller green and are not considered high quality by today's standards. Mummies were often buried with emeralds. The rich green gems were popular in ancient Rome, but many of the stones called emeralds in ancient times were actually modern-day peridot.

Traditionally, emeralds are worn to promote healing and enhance love and contentment. Emeralds are also thought to enhance the insight of their wearers. 

Common Emerald Treatments

Most emeralds are treated to enhance their appearance. Even though treatments are common and accepted, they should be disclosed to buyers. Nearly all emeralds are treated with oils or epoxy resins to fill-in surface cracks, making the cracks less visible and improving transparency. Some coating oils are clear; some are tinted green to make the emeralds more vivid.

Most jewelers will tell you to avoid cleaning emeralds with ultra-sonic devices because that process can remove coatings.

When It's Too Good to Be True

When high-demand gemstones are scarce and costly, manufacturers will attempt to create products that look like the real thing. Emeralds are just one of many gemstones that can be grown in a lab.

The way synthetic emeralds are grown has changed, but they have been produced for many years. Some of the stones even have inclusions that make them look natural. True synthetic gems have the same chemical characteristics as their natural counterparts, but a reputable jeweler will disclose that a gem is lab-grown. Always ask if gemstones are created or natural. If you are buying an expensive gemstone, have it checked by a testing lab.

You'll run across fake or composite emeralds. A composite is a smaller piece of a desirable, genuine stone that's been combined with a larger chunk of an inexpensive or imitation gemstone. It's often difficult to detect these stones without magnification. 

What you think is an emerald might be a fake made of glass or another material. Glass and other materials are sometimes used to mimic an emerald.

So if you've found a beautiful hunk of green at that flea market, and it even has inclusions like a real emerald, buyer beware! 

Edited by: Lauren Thomann