5 Things to Know About … Taaffeite
By Brecken Branstrator
brecken.branstrator@nationaljeweler.com
June 15, 2020
Five taaffite gemstones from Pala International weighing (clockwise from top left): 2.45, 1.36, 1.35, 0.79 and 1.32 carats
"In gemstone history, spinel plays the role of the great imposter. Numerous “rubies” set in royal or other treasured jewels turned out to be spinels.
But, as it turns out, there’s another gemstone that rivals spinel when it comes to identification confusion.
Enter taaffeite, a very rare gemstone that looks similar to spinel but isn’t as well known.
Taaffeite can come in various pink and purples shades like lilac, violet and mauve, as well as red, brown, bluish hues, gray, green and colorless.
I happened upon the gem while scrolling through Instagram, as one does, and immediately added it to my list of stones to cover.
I’m so glad I did; there are many interesting things about this gem beyond just its rarity, though that is of course one of its more notable aspects.
Here are five things to know about taaffeite.
1. It was long mistaken for spinel.
One of my favorite parts of researching this stone was hearing the story of how it was “discovered.”
In 1945, gemologist Count Edward Charles Richard Taaffe of Dublin, Ireland was sifting through a parcel of cut and polished stones.
While examining them, he realized a small mauve-colored stone weighing 1.419 carats that looked like spinel might be something different.
Importantly, the gem was doubly refractive. Spinel, like diamond and garnet, is singly refractive.
Curious and wanting to investigate further, Taaffe sent the gem to the Laboratory of the London Chamber of Commerce for testing.
A 13.23-carat oval mixed-cut purple taaffeite from Sri Lanka (Image courtesy of the Dr. E. Gubelin Collection. Photo credit: Robert Weldon/GIA)
Researchers eventually confirmed it was a new species and named the stone after the gemologist.
Part of the new gemstone was used for analysis, and the remainder was returned to Taaffe as a 0.55-carat stone, according to the International Gem Society (IGS), standing as the first official chunk of taaffeite.
Taaffeite is the first, and still only, gemstone initially identified from a faceted gemstone.
Carl Larson of gem dealer Pala International called this “extraordinary” since cut gems are harder to identify than rough as an observer loses “clues” like the crystal system.
2. Here’s how it’s similar to, and different from, spinel.
At first glance, many taaffeites looks just like spinel. It’s once you get into the specifics that you’re able to spot the differences.
The two gemstones have a similar hardness (8 for spinel, 8 to 8.5 taaffeite), refractive index (1.1712-1.762 for spinel and 1.719-1.730 for taaffeite), and specific gravity (3.54-3.63 for spinel and 3.60-3.62 for taaffeite).
But, as mentioned above, taaffeite’s birefringence sets it apart.
Taaffeite also has a different chemical composition and crystal structure than spinel. Spinel forms in cubic crystals whereas taaffeite forms in the hexagonal crystal system.
3. It originates from only a few sources around the world.
The source of taaffeite was unknown for a long time. Eventually, small fragments were found in Sri Lanka and southern Tanzania, according to reference site GemDat.org.
Material also has come from Myanmar, and some lower-grade taaffeite has been found in China and Russia, according to the IGS.
It’s not surprising the gemstone has been mistaken for spinel, not only because of its similar appearance but also because, according to Gems & Gemology, it’s found mixed in with parcels of spinel.
This oval-shaped taaffeite from Multicolour weighs 3.44 carats and is from Tanzania. (Photo credit: Vanutsaporn Treemok)
4. And it is rare.
For many years after Taaffe’s discovery, there were only known to be a few samples, and taaffeite remains one of the rarest minerals in the world, IGS said.
An article in the summer 1982 issue of Gems & Gemology said only about 10 specimens had been identified at that time, and estimates for how much taaffeite is currently in circulation today remain fairly small.
Due to its incredible rarity, it’s used exclusively for cut gemstones, multiple sources said.
Larson said he’s only worked with about 20 taaffeite stones in his seven years with Pala International, adding he’s only sold four stones he’d call fine quality.
According to Bonhams, the few taaffeites seen on the market are usually light in color and small.
5. There are ... "
https://www.nationaljeweler.com/blog/88 ... -taaffeite
