If you’re looking for a rare and unique gemstone to add to your collection, then you should consider the alexandrite. This stone is so rare that it’s often called a “treasure” worth hunting for.
If you develop an obsession for acquiring this gemstone, then it will keep you quite occupied for many years and the money you keep saving by not finding one right away will help pay for it as long as you have not given up and settled for buying an entirely different gemstone.
In this article, we’ll discuss the history and properties of the alexandrite gemstone.
We’ll also talk about how to find and purchase this stone. So if you’re ready to add some luxury and rarity to your life, keep reading!
Table of Contents
What is an Alexandrite Gemstone
Alexandrite is part of the chrysoberyl family along with chrysoberyl which is known as “cat’s-eye”. This family of stones is noted for having a high refractive index and strong pleochroism.
Alexandrite was discovered in the Ural Mountains of Russia in 1830 and gets its name from Alexander II, who was the Czar at the time.
Alexandrite appears bluish-green in sunlight or fluorescent light, but will change to a variety of reddish-purple or purple-gray under incandescent lighting or candle light. This is due to the saturation of the light spectrum inside the stone as it plays with the light source.
Alexandrite has trace amounts of chromium and this element also makes emeralds green.
Alexandrite’s are sometimes mistaken for emeralds because it will always be green in natural sunlight and they require incandescent light to change colors.
One must not confuse alexandrite from chrysoberyl even though they are from the same gemstone family.
The primary difference between the two is that color changes as a function of the light source in alexandrite being green, whereas chrysoberyl is normally yellow, yellow-green or brownish due to the presence of iron.
Alexandrite results from the small scale replacement of aluminum by chromium in the oxide which results in the characteristic green to reddish color changes.
It’s rarity is due to the two kinds of minerals.
Only chrysoberyl displaying a distinct change of color should be designated as alexandrite. But because there is some weak color change in chrysoberyl, it can be subjective.
A strong and obvious color change is most desirable. Chrysoberyl also shows no fluorescence whereas the red fluorescence of alexandrite is only evident by using the crossed filter method.
As you can note, it is best to have a Certified Graduate Gemologist examine any stone before buying it so that you do not end up with chrysoberyl rather than alexandrite.
How Rare is Alexandrite?
Alexandrite is so rare that most jewelry stores do not have any in their inventory that you can look at. Nevertheless, they can be found if you are willing to look long and hard and don’t give up easily.
Sometimes you will have to procure one from outside your country, but beware, you must enlist the help of a local jeweler who has a relationship with a gemstone dealer who has access to the few mines or gemstone dealers that they come from.
Add to that the fact that alexandrite is typically untreated, unlike 95% of all colored gemstones since the 1960’s.
While imitations do exist, they can be identified with the use of special tools and techniques that modern appraisers use in their work.
Actually, even lab grown Alexandrites, although significantly lower in price, are still not affordable for the average consumer.
Apart from the Ural mountains in Russia, this gemstone is also found in a few small deposits in Brazil, Sri Lanka, Burma, Madagascar, and Tanzania.
What Makes Alexandrite So Rare
As you can imagine, Alexandrite has some special properties that make it not only rare but also unique. For starters, as we’ve noted, it is one of the few gemstones that change color. In fact, it is the most dramatic and complete color change of any gemstone.
Here are a few reasons why Alexandrite is so rare:
Optical Abnormalities
There is an optical phenomenon that is in play with an alexandrite.
A visible white stripe in the center of the gem that makes it appear as a cat’s eye called chatoyancy is present.
When the gem is moved back and forth in fluorescent light, the white stripe beneath its surface does the same and this is also present in aquamarine, tourmaline and moonstone.
Star sapphire exhibits this same type of phenomenon but is seen in all light types and has more stripes.
Gemstone Hardness
Alexandrite is runner up to sapphire in the Mohs hardness scale, ranking 8.5. This feature makes it highly favored in jewelry given the fact that it is so expensive.
This property makes it easy to work with without worry about damage, unlike emerald, opal or other soft gemstones.
Sapphires are slightly harder ranking at 9 and diamond is the hardest ranking at 10 on the Mohs scale.
Trace Minerals
Alexandrite is very rare because its chemical composition has an extra trace element in addition to iron and titanium.
While chrysoberyl has those two elements, alexandrite has the trace presence of chromium that gives it the emerald-green hue in daylight.
The presence of chromium is what makes Alexandrite so unique and rare.
How Much Are Alexandrites Worth?
Now it’s time to talk money.
Alexandrites are worth a lot.
They are one of the most expensive gemstones on the market and have been since they were first discovered in Russia’s Ural Mountains.
The price of an alexandrite can range from $10,000 to $50,000 per carat depending on its size, quality, and color-change properties.
While most people will never be able to afford an alexandrite, they can take solace in the fact that this gemstone is so rare that it is highly unlikely they will ever come across a fake.
Let’s take a look at how the prices of different Alexandrite gemstones compare:
Natural Alexandrite
As of today, a one carat alexandrite gemstone can fetch around $15,000. Anything bigger, if you can find one, will go for between $50,000 and $75,000 for each additional carat.
Of course, the quality of an alexandrite will play into the price too, but even a heavily included stone will fetch quite a bit of money depending on the size.
Treated Alexandrite
When it comes to gemstones and luxury jewelry, one thing you never want to do is purchase treated stones.
The value of a gemstone is diminished significantly when it has been treated in any way.
Nevertheless, natural Alexandrites are usually not treated because they cannot be improved by any kind of thermal treatment.
This has already been tried and it is found that heat does not affect alexandrite at all.
Some lower quality cracked alexandrites are oiled in an attempt to hide the cracks similar to what is typically done to poor quality emeralds. But in general, alexandrite is not known to be treated in any way.
Synthetic/Lab Grown Alexandrite
There has been an alexandrite-like sapphire material that has been around for almost 100 years.
This material shows a characteristic purple-mauve color change which is quite attractive, but it does not really look like an alexandrite because there is never any green in it.
These are actually synthetic corundum laced with vanadium that produces the color change.
The stones are very clean and are available in large sizes which is rare in natural alexandrite.
Under magnification, gas bubbles and curved stria are observed.
Since synthetic alexandrites share the same chemical and physical properties with the natural alexandrites, a regular gemologist test for density and refractive index is worthless.
However, what can be seen are curved striations that are visible with magnification and will confirm that a stone is synthetic because natural alexandrite will never show curved growth lines.
The other thing to note is that natural alexandrite must be green in natural light. Synthetic/lab grown stones will pull from blue to red which are very pretty…
…but they are still not alexandrite.
Last, flux grown alexandrite is more difficult to identify because the inclusions of the undissolved flux can look like natural inclusions.
It will contain particles that resemble liquid feathers with a refractive index that is exactly the same as a natural alexandrite.
Strong banding or growth lines may also be apparent giving the necessity for further professional examination by a company such as GIA.
Final Thoughts
Alexandrite is one of the most amazing and rare gemstones in existence.
If you are lucky enough to come across one, it will be a treasure worth keeping. Just be sure that you are getting the real thing by having it examined by a professional.