3 Taaffe was sorting through a parcel of cut and polished Sri Lankan spinel gemstones when he discovered something that he knew could not be spinel since it was doubly refractive (spinel is singly refractive). This is one of the rare cases where the first sample of a new gem variety was found in the form of a faceted stone.
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.
4 The originally discovered taaffeite came out of a lot of mauve spinels and weighed 1.419 carats; part of this stone was analyzed, and the remainder was recut into a gem of 0.55 carat. This was presented to the discoverer, Count Edward Charles Richard Taaffe, a Bohemian—Irish gemologist living in Dublin. A second stone identified as taaffeite weighed 0.86 carats and is now in the Geological Museum, London. A third taaffeite of 0.84 carats, identified at the Gemological Institute of America laboratory in New York, resides in the S1collection along with a dark brownish-purple gem of 5.34 carats. Many other stones have been identified, perhaps as many as 50.
5 Apart from being doubly refractive, taaffeite has many similarities to spinel. It is very hard, with a Mohs hardness rating of 8 to 8.5, whereas spinel has a score of 8. Taaffeite has a specific gravity of 3.60 to 3.62, almost identical to that of spinel (3.54 to 3.63); and a refractive index of 1.719 to 1.730, also similar to spinel, which has a refractive index of 1.712 to 1.762. By chemical composition, taaffeite is magnesium beryllium aluminum oxide (whereas spinel is magnesium aluminum oxide). The most common inclusions in taaffeite are apatite and zircon crystals.
6 A rare and beautiful mineral,Taaffeite is known to be colorless, violet, red, green or blue. The most common colors are fairly unsaturated mauve and lavender. Taaffeite may be transparent to translucent in appearance.
7 Deeper red and purple Taaffeite, colored by traces of chromium and iron, is extremely rare. Of the rarest red variety there are fewer than ten specimens.
David Weinberg of gemstone wholesaler Multicolour said they are seeing a few very specific markets for taaffeite: collectors, engagement rings and collector-investors.
While he noted demand has dipped in light of the coronavirus pandemic, it is still “generally better” than most stones, a performance he attributes to the increasing popularity of rare gemstones. (https://www.nationaljeweler.com/blog/8886).
Always purchase from a reputable sellers and competent gemologists.