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Meet the Alexandrite, one of the world’s rarest gemstones! 

By Danielle

Senior diamond consultant; standing by to provide personal advice. She knows exactly what you are looking for while keeping your budget in mind.

June 15, 2021

The world of gemstones is immense. So far, there are more than 300 different types of gemstones discovered. The ruby, emerald, and, of course, the diamond sounds familiar to you, but there are many gemstones you might not know about. Many of them are very rare, and in this blog, we highlight one of the rarest gemstones of them all: alexandrite.

What is alexandrite?
Alexandrite, known to researchers as chrysoberyl, is a gemstone that changes color, depending on the light. Alexandrite is composed of two minerals: chromium and beryllium. Both minerals must be present to form chrysoberyl. The stone was discovered around 1830 in the Ural Mountains in Russia. This gemstone was different because of the unusual green color that changes in the light. The discoverers had never seen this spectacle and the first person to see it was Nils Gustaf Nordenskiöld, a famous mineralogist from Finland.

alexandrite, gem alt text: alexandrite, gemological institute of America, GIA, red, green

Alexandrite, photo by the Gemological Institute of America

Where does the name alexandrite come from?
In 1834, the gemstone was named after the then future Czar (Emperor of Russia) Alexander II Romanov – Alexandrite. And it’s the last part that we name the stone today.

What are the characteristics of alexandrite?
Alexandrite’s best-known property is the changing of color. The basic colors are green and red; the stone is green under day-, and sunlight and changes to a red color under an electric light bulb. When the stone is placed under other light sources it also reflects other colors. The table below shows what other colors alexandrite produces. Incredible, right?

color changing, alexandrite alt text: alexandrite, lamps, color changing, light, gemstone

Changing color of alexandrite under different lights

Alexandrite is usually mined in small sizes. Most stones are relatively small and weigh less than 1 carat (0.2 grams). The largest alexandrite ever found is a 65.7-carat stone from Sri Lanka and the largest alexandrite from the Ural Mountains weighs about 30 carats.

What determines the value of alexandrite? 

The intensity of the color
As with diamonds, the value of alexandrite is determined by several criteria (4Cs for diamonds). The most important criterion to determine the value of alexandrite is the color and especially the intensity. The deeper and more intense the color, the higher the value.

The percentage of color change
However, the hue of the color does not always directly affect the value of the gemstone. The hue can show where the alexandrite was mined, we will cover this in a moment. The second criterion is the degree of color change. Not only must the colors red and green be vivid, but the change of colors must also. In fact, Alexandrite has a rich range of color changes, starting from 5% to 100%. It wouldn’t surprise you if we say that the higher the percentage of color change, the higher the value.

The clarity
The next criterion is the clarity of the stone. Like most gemstones, alexandrites aren’t always loupe-pure. It is noteworthy, however, that clarity isn’t a priority in determining the value of alexandrites. The factors that do have priority are color intensity and color change.

This would mean that an alexandrite with intense colors and opaqueness would be worth more than a light-colored alexandrite that is loupe pure. However, this doesn’t mean that clarity isn’t important at all in determining value. An intensely colored alexandrite that is also flawless is obviously in the best class! Unfortunately, these varieties are even rarer than they already are.

Carat
The final criterion is carat, which strongly influences the value of the stone. Although most mined alexandrites weigh less than 1 carat, these stones can have a value of €15,000 per carat. Alexandrites weighing more than 1 carat can even be worth €50,000 to €70,000 per carat. 

Ural Mountains, alexandrite alt text: Ural Mountains, alexandrite, gemstone, mined, 1832

The Ural Mountains is where alexandrite was first mined

Where is alexandrite mined?
The original source of alexandrite is the Tokowaya Valley (Ural) in Russia. Since 1987, alexandrite has also been found in other locations such as Sri Lanka, Brazil, Zimbabwe, and Myanmar.

The stones from these mines may have different hues than stones from the Ural Mountains, but the basic colors are always green and red. These different shades don’t directly affect the value of alexandrite, but stones from the Ural Mountains are considered the best in terms of color change.

What is an alternative for alexandrite?
Because alexandrite is difficult to obtain (and therefore expensive), the best alternative is to look for synthetic alexandrite. You read that correctly: synthetic alexandrite, called “lab-grown” in a nicer way. These gemstones, like natural alexandrite, are made with chromium and beryllium.

Synthetic alexandrite is considered to be a real alexandrite because it is made up of the same minerals. Therefore, you don’t have to worry about whether the synthetic variety will be viewed as fake. And there are also two advantages:  

  1. Synthetic alexandrite is made ‘by hand. Therefore, the price is lower than a ‘natural’. 
  2. Natural alexandrites are often not cut into shapes other than a cabochon. With synthetic alexandrite, the stone can be cut into the shape you want. 

So this means you can enjoy the beautiful properties and decide on the shape yourself.

imitation alexandrite: imitation alexandrite, corundum, color change, imitation, crystal, synthetic

An imitation alexandrite stone

However, beware of imitation alexandrite. This isn’t the same as synthetic alexandrite, as synthetic alexandrite is made with the same minerals as the natural variety. Imitations are made with corundum, a crystal that also changes color. 

You can recognize a “faker” by the color; the imitation stone is mauve or purple. The second indicator is price. When alexandrite is offered at a low price it often means ”too good to be true.” Not sure if you have a genuine alexandrite in your hands? A gem expert or a prominent institute will tell you if you are dealing with an original alexandrite.

Today you have been introduced to alexandrite and its wonderful characteristics. Do you own an alexandrite? Congratulations! You are the proud owner of one of the rarest stones in the world! Want to learn more about the wonderful world of diamonds and gemstones?  Book a tour at Royal Coster Diamonds and be inspired by our experienced diamond consultants. 

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