Few people have actually laid eyes on an authentic alexandrite gemstone. That’s because this beautiful color-changing gem is incredibly rare and only found in a few places on the planet. As you can imagine, the limited supplies of the gem make it incredibly valuable and coveted by jewelers, gemologists, and anyone with a love for precious stones. If you do come across the stone, there are a few things you should know about alexandrite.

What is Alexandrite?

Alexandrite is a form of chrysoberyl that changes colour depending on the light. In daylight it shines a green color, while in incandescent light it reflects a reddish hue. The hues can range from pure green and red to green-ish blue, purple, brown or rust colors. Some gems exhibit a complete colour change in different lights, while others exhibit only a slight change. Alexandrite stones can also contain inclusions that give them a cat’s eye look.

The History of Alexandrite

The first reports of alexandrite being discovered were at an emerald mine next in the Ural Mountains of Russia in the 1830s. One day miners gathered stones that they thought were emeralds, but when they looked at them in the evening, the gems had changed to a reddish color. The new stones were a hit with the Russian aristocracy, and by the 19th century, most of the stones in Russia had been mined. Later there were deposits found in Sri Lanka, Brazil, and East Africa. To this day, these are the only known places where alexandrite can be mined.

How Valuable is Alexandrite?

There are a number of factors that drive up the value of an alexandrite stone. The first and most important is the percentage of color change. A stone that changes color by 100 percent will be more valuable than one that doesn’t exhibit a high percentage of change. Pure green and red stones are prized over those with murkier colors. Clarity is another factor. Stones with inclusions are less valuable than those that have no inclusions. And of course size is also important. A high-quality alexandrite gemstone can command as much money per carat as a diamond.

Often called ’emerald by day, ruby by night’, alexandrite is a stunning stone that is incredibly rare and hard to replicate. If you do come across one, be sure to check it for pure hues, the rate of color change, and its clarity. If it has all of those characteristics, you’re looking at a very valuable stone.