Taaffeite Gemstones
June 3, 2020

What Are Taaffeite Gemstones ?

Reputed as one of the rarest gemstones in the world, taaffeite is indeed a wonderful creation of Mother Nature. Given its rarity, taaffeite gemstones are mostly popular among gemstone collectors. Taaffeite is easily misidentified as spinel since it almost impossible to differentiate the two with the naked eye. This is another reason for the extreme rarity of this stone as most taaffeite are sold as spinels.

History of Taaffeite

The stone was named after the gemologist Richard Taaffe from Dublin – Ireland, who discovered this mineral. He made this discovery in 1945 when he noticed something unique about a particular small mauve stone which was among the stones he bought from a jewelry shop in Dublin. His instincts might have told him that the stone is different from spinels and he has sent it to the laboratory at the London chamber of commerce and later to the Museum of Natural History for testing. After the testing, it was confirmed that the stone Taffe found is a new form of mineral which had not reported before.

(You can read the fascinating story behind the discovery from the own words of Richard Taaffe here)

This discovery makes taaffeite the first gemstone to be found in the faceted from.

IMA (International Mineralogical Association) approved the name Magnesiotaaffeite-2N’2S for taaffeite in 2002 (2N stands for the two Nolanite modules and 2S stands for the two Spinel modules).

image 1: A Taaffeite Gemstone From Sri Lanka

Physical Properties of Taaffeite Gemstones

As stated before, taaffeite gemstones are often confused with spinels. Taaffeite color range falls right inside the color range for spinels and there are similar structural features as well. Reported colors of taaffeite are colorless, grayish, violet, violet red, red, light green, greenish, pink, violet and mauve. Red stones which are colored with chromium are considered the rarest.

However, taaffeite is a doubly refractive stone which helps to differentiate from spinel which is a single refractive stone.

But adding to the difficulty of identification, there are spinels which displays anomalous double refraction. Hence, a proper testing for double refraction is needed to identify taaffeite. Due to the existence of anomalous double refractive spinels, polariscope testing will not yield accurate results.

(In Sri Lanka, where I am from, merchants have come up with a simple low cost polariscope, which can differentiate single refractive stones with the rest. Similar tools might be available in other countries as well. But, this tool is also not capable of differentiating double refraction with anomalous refraction.)

The main components of taaffeite are beryllium, magnesium, and aluminium. This was confirmed in 1951 through x-ray analysis. Therefore, taaffeite is also the first mineral to contain both beryllium and magnesium as main components.

Following table summarizes the main physical and chemical properties of taaffeite.

Chemical Composition BeMgAl4O8 (Ideal formula is Be4Mg4Al16O32)
Crystal System Hexagonal
Hardness 8 – 8.5
Specific Gravity 3.60 – 3.61
Refractive Index 1.722 – 1.777
Birefringence 0.055
Pleochroism Weak

Sources of Taaffeite

So far, most taaffeite have been found from Sri Lanka alongside other carbonated stones such as fluorite and spinel. Taaffeite has also reported from southern Tanzania. More recently, taaffeite samples were discovered in Myanmar and South Australia. Lower grade taaffeite were reported from Russia and China.

image 2 : Some Faceted Taaffeite Pieces

Known Taaffeite Pieces

The first piece of taaffeite found by Richard Taaffe was a 1.419 carats mauve color piece. The largest known taaffeite is a 33 carat specimen which was sold in an auction in 1999 in Hong Kong.

Geological Museum in London has a taaffeite of 0.86 carats and the Gemological Institute of America laboratory in New York contains two pieces weighing 5.34 (brownish purple) and 0.84.

A gem collector in Sri Lanka owns an oval shape mauve taaffeite free of inclusions, which is 13.22 carats. Two more stones with 10.13 carats and 11.24 carats along with a number of other small stones are reported from some other collections. 10.13 carats is a gray-mauve stone with oval cut and the 11.24 is a pink stone.

Another 3.04 carat pale mauve stone was reported from Burma.

These records might give you an idea of how rare and valuable this gemstone is, especially for collectors.


Taaffeite vs Musgravite

Musgravite is another very rare gemstone which has many similar properties to taaffeite. The difference between Taaffeite and Musgravite lies in the magnesium content. Since all other properties are almost identical, Raman Spectroscopy test is used to differentiate these two stones. Through this, molecules can be identified by a creating a structural fingerprint.

Musgravite was given its name because of the Musgrave Ranges of Southern Australia where it was first discovered. Due to its relationship with taaffeite, IMA gave the name Magnesiotaaffeite-6N’3S to musgravite (6 Nolanite modules and 3 Spinel modules).


Taaffeite Mineral Group

As earlier stated, taaffeite is the name of one of the rarest gemstones. But after the discovery of taaffeite, two more related minerals have been found. One is Musgravite which was introduced earlier in this article, and the other is Perhmanite, which is known as Ferrotaaffeite-6N’3S.

Therefore, IMA has approved the name Taaffeite for this mineral group. However, in the gem trade, taaffeite and musgravite are still used as individual names for those two gemstones and it will probably continue to be regardless of scientific names and the IMA approved name for the group of minerals.


Taaffeite Price Per Carat

Given the rarity of taaffeite, it attracts high prices. Since reddish colors are rarer, prices of such stones will be even higher.

As a generic guide, the price per carat can vary between $1,500 and $2,500. As the carat size increases, the prices will be much higher.

Here is a video which shows a raw taaffeite gemstones.

Final Thoughts

Because taaffeite gemstones are rare and also because it is a recent discovery, information regarding this stone is not available as readily as in the case for some of the more popular gemstones. Hence, the objective of this article was to provide you with all the important information you need to know about taaffeite.

As discussed in this article, taaffeite is also a name used for this mineral group but the article was specifically intended to introduce the taaffeite gemstone.

Hope you found value in this article and if you did, it will be great to hear your comments. Please also let me know any questions you may have.

4 thoughts on “What Are Taaffeite Gemstones ?

  1. A really interesting post. What a beautiful stone the Taaffeite is. It’s very interesting that the stone is rare and expensive to purchase.

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