2025.2.27 My favorite chrysoberyl

Good morning, this is Nori-chan.
"A relaxing way to kill a few minutes of time!" "A little special news!"
We would like to provide information to help you enjoy gemstones at GemTreeJapan.



Chrysoberyl, whose Japanese name is "kinryokuseki," is a sparkling, hard mineral, and for some reason, it's Nori-chan's favorite type. In this article, we'll learn a little about chrysoberyl.


Although I wrote that chrysoberyl is a hard mineral, its Mohs hardness is 8.5 ( *1 ), which is harder than topaz and spinel (7) and softer than corundum (9).


Although Wikipedia does not list it as a precious stone ( *2 ) , some chrysoberyls are highly valuable because they are sufficiently hard and, depending on the quality and type, the cost of the stone exceeds the cost of polishing. Their brilliance alone makes them potentially valuable as precious stones. Cleavage is present and clear in two directions.


*1 This is based on the Japan-Germany Gemological Institute. Some articles list alexandrite and cat's eye as having a hardness of 8, but the Japan-Germany Gemological Institute lists them all as 8.5.

*2 The criteria for precious stones are rarity, hardness, and beauty. Hardness is easy to understand as it is 7 or above, but there is ambiguity regarding the level of rarity and beauty. There also seems to be no clear distinction between precious and semi-precious stones.


Chrysoberyl comes in a range of colors from yellow to green and brown, with rare colorless and red . The basic color range is yellow to yellow-green. Currently, GemTreeJapan mainly handles yellow.


The colour triggers and names are as follows:


The photo below shows a predominantly yellow chrysoberyl. The yellow color is due to iron ( Fe ) . As the iron content increases, the color turns brown. This is often the case with sphene, sphalerite, and other minerals, but as the iron content increases, the color tends to approach black.

The photo below shows a small parrot chrysoberyl with beautiful fluorescence. Originally, the term referred to highly saturated parrot-colored chrysoberyl found in Orissa, India, but now it seems to refer to stones with the same hue, regardless of their origin, like padparadscha sapphire and Paraiba tourmaline. It gives the impression of having a hint of green.


The photo below shows a colorless version of chrysoberyl, which is found in various minerals. White (colorless) chrysoberyl contains very little iron. There are many minerals that exist as colorless crystals , including spinel and corundum. Chrysoberyl is It is BeAl2O4 , and iron ( Fe) is an impurity . If there is little iron, it will be closer to colorless. If it does not contain iron, it seems to be indistinguishable from artificial chrysoberyl, but what about now?


Green, mint-colored chrysoberyl is either vanadium ( V ) or chromium ( Cr )
Alexandrite is obtained by adding more chromium ( *3 ) and exhibiting a color-changing effect. Below is an image of alexandrite.

*3 To be precise, the aluminum ( Al ) that makes up chrysoberyl is substituted (switched) with chromium and enters the structure. Alexandrite has the same chemical formula as chrysoberyl.


To be honest, there are so few examples of red chrysoberyl that I couldn't research it. There is only one example of red chrysoberyl in Japan in the past few years , so it is likely to be very expensive. Nori-chan has never even seen one in person, let alone held one in her hands.


The fluorescence reaction of chrysoberyl is generally red. Vanadium and chromium show a fluorescence reaction, so green chrysoberyl generally fluoresces . Colorless chrysoberyl also fluoresces, although not strongly. What triggers this fluorescence?

The fluorescence image above shows the fluorescence of the yellow-based chrysoberyl introduced first. It is not as strong, but it does show a fluorescent reaction. The white chrysoberyl shown above also shows a similar or slightly stronger fluorescent reaction, but in either case it is considered weak fluorescence. However, the alexandrite in the fluorescence image below contains enough chromium that it fluoresces as strongly as ruby.



There are also some that have the cat's eye effect . It is the birthstone for February, and although we do not currently carry cat's eye stones, we are focusing on selling chrysoberyl as our main focus this time .


Next, from a mineral collector's point of view, there are quite a few sources of chrysoberyl. Most of the chrysoberyl handled by GemTreeJapan comes from Sri Lanka. Other sources include Brazil, Tanzania, Madagascar, Russia, and India.


The Sri Lankan gems we deal with are particularly well-known, and although beautiful cat's eye gems have apparently been mined in Ratnapura, the current production is mainly brown gems with a high iron content. This is also a famous source of sapphires . Sapphire is aluminum oxide ( Al2O3 ) , and chrysoberyl is a form of sapphire with beryllium ( Be ) added, so perhaps this is not surprising.


This article is a summary of some things that are good to remember.
①Hardness is 8, but there is clear cleavage in two directions.
②There are quite a few colors, and the beautiful green, parrot color, is particularly expensive.
There are no completely colorless or red ones to begin with. If you find one and think, "It's cheaper than I thought," then it's worth buying immediately to add to your collection.
③ There are quite a few origins, and although they are general, there are still some distinctive characteristics.
④Alexandrite is a variety of chrysoberyl.


In the end, it's beautiful! That may be all that matters.
We are offering amethyst and chrysoberyl at special prices until February 28th, and if you purchase a single or multiple items worth over 100,000 yen, you will receive one stone free if you add them to your cart, so be sure to take advantage of this opportunity to get your hands on one of GTJ's sparkling pieces.