Taaffeite: The Accidental Discovery Behind One of the World’s Rarest Gems

In 1945, a routine examination of faceted gems in a Dublin jewelry shop led to the identification of taaffeite — one of the world’s rarest gemstones — after a single mauve-colored “spinel” behaved in ways no trained gemologist would expect.

The story goes something like this: Count Richard Taaffe, an Austrian-born gemologist living in Ireland, was examining a parcel of stones believed to be spinel. One of the gems stood out because it looked like spinel, but it didn’t behave like one. Under magnification, Taaffe noticed something extraordinary: the stone was doubly refractive, bending light in two directions. Spinel, like diamond, is singly refractive.

Intrigued, Taaffe sent the stone to the Laboratory of the London Chamber of Commerce for testing. The verdict was historic. The gem wasn’t spinel at all — it was a previously unknown mineral species, later named taaffeite in his honor. To this day, taaffeite remains the only gemstone ever first identified from a faceted stone, rather than rough crystal.

Chemically, taaffeite is a magnesium aluminum beryllium oxide, placing it in a mineral group closely related to spinel and chrysoberyl. On the Mohs scale, it measures 8 to 8.5, making it durable enough for jewelry, though its rarity means it’s most often reserved for collectors. Taaffeite is prized for its soft yet luminous color range — most commonly lavender, mauve and violet, though pink, red, green, blue and even colorless stones are known.

What truly elevates taaffeite into gem-world legend is its scarcity. It’s often described as millions of times rarer than diamonds, and it belongs to an ultra-exclusive group frequently cited as the three rarest gemstones on Earth: taaffeite, painite and kyawthuite. While painite and kyawthuite may edge it out for the absolute top spot, taaffeite remains one of the rarest gemstones ever used in jewelry.

For decades after its discovery, only a handful of taaffeite specimens were known. Today, gem-quality material comes primarily from Sri Lanka and southern Tanzania, with smaller finds reported in Myanmar, and lower-grade material in China and Russia. Even now, stones are usually discovered mixed in with parcels of spinel, explaining why so many were overlooked for so long.

Prices vary widely based on color and clarity. Lighter stones may trade around $1,500 to $2,500 per carat, while finer, more saturated examples can command $5,000 to $7,500 per carat — and exceptional stones with rich color and eye-clean clarity have sold for $15,000 per carat or more.

For collectors and gem lovers, taaffeite represents the ultimate insider gemstone: rare, beautiful and born from one of the most remarkable accidental discoveries in jewelry history.

Credit: Conceptual illustration of taaffeite by The Jeweler Blog, generated by aichatapp.ai.