by Ron Campbell Central Coast Gem Lab
Recently, we’ve received a number of questions about the “true” color of Alexandrite. We’ve also received questions about the color change needed for a reputable gemological lab to correctly classify a gem as Alexandrite. Many gem enthusiasts and buyers are sold color change chrysoberyl, and they are almost always told by the seller that it is Alexandrite. Please be careful – not all color change chrysoberyl is Alexandrite! They are different varieties of the same gem, but there are strict standards for color shift in a Chrysoberyl that have to be observed under specific lighting conditions before that Chrysoberyl can correctly be classified as an Alexandrite.
Here is the classic definition of Alexandrite’s color change ranges:
|Daylight (sunlight)||Incandescent light|
|blue Green||orange Red|
|very slightly blue Green||Red|
|Green||slightly purple Red|
|slightly Green||Purple Red|
|yellow Green||Red purple or Purple red|
You should not have to guess about these color changes, nor should the color change be feeble. In a correctly classified Alexandrite, the color change is very dramatic and obvious. Any of these combinations that are observed in a particular Chrysoberyl can and should be identified as Alexandrite and classified as such. No other color combinations should be called Alexandrite. Rather, they are more appropriately referred to as color change Chrysoberyl.
Historically the origin of fine grade Alexandrite has been the Ural Mountains. However, recent finds of good material from Brazil and some East African countries, exhibit a good to fine color change in the prior described color ranges.
There is also great deal of gem-quality material being sourced from various areas in South America, East Africa, and Sri Lanka. The color change in that material typically ranges from Green to Yellow, brownish Red to Purple, or yellow Green to blue Green. Other combinations are occasionally seen as well.
Note: In color descriptions, a capital letter on one hue means it is the dominant color. Those beginning with a lower case letter are the less dominant or secondary color. So, when you see the color description written as; Green yellow, or Red purple, this tells you which is the dominant and which is the secondary color.
What to watch out for when buying Alexandrite
Please be careful! Many of the stones I mention above have been marketed as Alexandrite and commanded very high prices. While they exhibit a dramatic color change, they should not be considered Alexandrite.
Do not be fooled into purchasing a color change Chrysoberyl in place of Alexandrite. Many of these stones can be seen on various T.V. shopping networks, and they are not a good deal.
Price should almost always be your first clue; just a good grade of Alexandrite, in a size range of 1-2 carats, can easily command a $2,500 – $4,500 per carat wholesale.
Note the color change description next. Bear in mind that, if the color change does not match the above criteria, when sent to a gemological laboratory, it will not grade out as Alexandrite.
A color change chrysoberyl is not a common stone and also demands a hefty price. They are a great addition to any gemstone collection, but be careful not to pay for an Alexandrite when you are not getting one. Buyer beware! Knowledge is power, and it is your best gemological tool to keep from being disappointed and keeping your hard earned dollars.