If May is your birth month, you have one of the most rare birthstones of all: Emerald.

To understand your birthstone, it’s important to know what it’s made of. Emerald is a variety of the mineral Beryl, with a vibrant green color due to the presence of Chromium. (There has been an addition to “emerald” of green gems colored by Vanadium but the classic emerald look comes from Chromium-rich beryl.)

Beryl found in other colors is known by other names, such as Aquamarine for blue beryl, Morganite for pink and peach beryl, Heliodor for yellow and golden beryl, Bixbite for red beryl (which has so far only been found in Utah), and Goshenite for colorless beryl. Chemically speaking, beryl is a Beryllium-Aluminum Silicate.

Interestingly, the red color in ruby is also caused by Chromium.

Where Does Emerald Come From?

Later in this article we will show you some of the countries where emeralds have been found from time to time. However, the real question people have has to do with current production in commercial quantities.

Right now South America seems to be the production king of emeralds. Colombia is now known as the source for the most coveted emeralds. The color of the best Colombian emeralds and the fine transparency of the crystals from Colombia make them the quality king.

What is it about the color of Colombian emeralds that people love? Well, first we have to talk about the color green. Green is a secondary color. Secondary colors are made from primary colors. In the case of green the primary colors are blue and yellow. But the actual shade of green can tip towards more blue or more yellow. Grass green, for instance, has more yellow in it when compared with the more bluish green of a fir tree.

(Road leading to an emerald mine in Columbia pictured at left.)  In the case of Colombian emeralds, the slightly bluish green tends to be very pure and not complicated by any overtones of other colors—blue + yellow + no additional overtones = a very beautiful Colombian emerald green.

That being said, even within the production of Colombian emeralds there are color and quality differences. From Chivor the emeralds are slightly more bluish green and from Muzo the emeralds are slightly more yellowish green. But taken as a whole Colombian emerald is slightly more bluish than emerald from Russia. Prior to the ascendency of Colombian emeralds to the pinnacle of desirability, Russian stones were considered the best. There may still be some debate over this issue, primarily in Europe.

The Goais region of Brazil

For the first 15 years or so of my career in gems, Brazil was known for producing emeralds in the state of Bahia—generally very poor quality emeralds. Then in the 1980s there were two discoveries of emerald in Brazil: Santa Terezinha, Goais and Nova Era, Minas Gerais. Interestingly both of these discoveries produced emeralds of startling beauty. Some of the best stones of Nova Era rivaled gems from Colombia—maybe not the finest from Colombia—but Nova Era gems can be beautiful. Santa Terezinha emeralds have distinctly more yellow than Colombian stones but have a uniquely undeniable beauty.

But let’s not leave out African gems. Zambia has produced lots and lots of large attractive gems. Usually in my experience though the Zambian stones have a color that is marred by overtones of gray. But the Zambian stones can be large and relatively clean and truly lovely in the better quality.

Where in the World?

However the following list is a list of places emerald has been found at one time or another. The extent of this list may qualify emerald as the rarest stone found in the most places. A good conundrum!

• Africa:  Egypt, Ethiopia, Madagascar, Mozambique, Namibia, Nigeria, Somalia, South Africa, Zambia, and Zimbabwe
• Asia:  Afghanistan, Cambodia, China, India, Kazakhstan, Pakistan, and Russia
• Australia
• Europe:  Austria, Bulgaria, France, Germany, Italy, Norway, Spain, and Switzerland
• South America:  Brazil, Colombia
• North America:  United States and Canada

What Makes Emeralds So Rare

As a young person in the gem world I was lucky enough to spend some time with Vince Manson Ph.D. who was, among other things, Curator of Gems and Minerals at the American Museum of Natural History in New York City, and Director of Research at GIA.

One of the things Vince talked with me about was the rarity of emerald. In Vince’s professorial way he helped me imagine just how rare beryllium is as an element and then to imagine how rare chromium is as an element and therefore just how rare it is that the two should ever cross paths in the crust of the earth. Just like any other occurrence in the world rarity plus rarity creates incredible rarity.

Now, if you add in the additional issue of good quality—the third variable—how rare must a fine emerald be! By way of illuminating this concept of rarity let’s have a little fun:

We’ll start by imagining a group of humans with some less common human traits, such as: 1. Women over 6 feet tall; 2. Left handed women; 3. Naturally red-haired women.

Now we’ll compare this with a second group containing more frequently occurring human traits, such as: 1. Women less than 6 feet tall; 2. Women who are right handed; 3. Women who are natural brunettes.

How much fewer women will there be of the first group as compared with the second group? This is my fun way of illustrating why fine emeralds are so rare: there are just too many unusual characteristics (variables) that must exist in the same gem.