One of the rarest gemstones in the world, very few samples of Taaffeite are known, although there are probably more specimens out there that have been mistaken for spinel. It was discovered in 1945 by Richard Taaffe, an Irish gemmologist and son of Viscount Henry Taaffe.
In October of 1945, he was examining a parcel of loose gemstones in the workshop of Richard Dobbie, a watchmaker and jobbing jeweller with a premises in Fleet Street, Dublin. Taaffe would sometimes visit Dobbie who allowed him to look through his gemstones and make an offer on any that interested him. Most jobbing jewellers keep a selection of loose stones (some would be precious gemstones, some semi-precious), to use in repairs and remounts. Taaffe would sort through the parcels of stones looking for additions to his collection. Dobbie himself would have been delighted to get paid for some old stones that had been in a box for years!
After several hours rummaging through boxes, Taaffe had a bundle of about one hundred stones. He paid for that bundle, then returned over the following two days to continue hunting! The total price paid was £14.
He took the stones home and starting sorting them, initially by colour. One lilac coloured stone was initially put in a pile with other violet and lilac stones. It weighed 1.41 carats. Then he looked at them under a microscope, checking for refraction (gemstones are categorised as singly or doubly refractive). This little stone was doubly refractive, the opposite of what would be expected for a spinel or a garnet.
Next he checked the specific gravity, and got a measurement of 3.62; again, this was intriguingly different (but very close to) spinel or diamond!
Puzzled, Taaffe sent the stone to B. W. Anderson at the Laboratory of the London Chamber of Commerce to see if he could identify the stone. He wrote:
‘This time a new riddle: what is this mauve stone? It seems to me to answer all characteristics of spinel, yet it shows double refraction: doubling of facets visible under the Greenough, extinction when polarized, though with queer colour effects. Could anomalous double refraction be so strong? R.I. too high for topaz, S.G. too low for corundum. What is it ?’
Anderson replied on November 5:
‘You have sent a most interesting stone in that mauve spinel (I call it that on the basis of its absorption spectrum: my colleague is so horrified at its anomalous optics that he doubts whether it is spinel). The indices are 1.717 and 1.721, clear double refraction, giving a clear uniaxial interference figure through the table facet. The stone is so remarkable that I should like your permission to have an X-ray analysis made, if possible without harming the stone. I should also like to write it up for the Gemmologist, giving full credit to you for discovering it. Would you agree?’
The article announcing its discovery, “Taaffeite, a new beryllium mineral, found as a cut gemstone”, was published in 1951, assuring Taaffe of his place in history. How exciting, how exhilarating it must have been, to have stumbled upon an entire new gemstone in such a humble location!
To enable X-ray and chemical work to be carried out, Taaffe agreed to portions of the stone being removed. This was an incredible gesture, as at the time it was the only specimen known! The cutting was carried out by Charles Mathews (Lapidaries) Ltd., in two stages, reducing the stone first to 0.95 carats, and then 0.56 carats.
It was not until October 1949 that a second specimen was found, a very pale mauve stone weighing 0.87 carats. Today, more specimens are known, though the number of Taaffeite stones in the world is still amazingly low, perhaps only a dozen confirmed cases of strong red colour.