What is "taaffeite"

n. (cx mineral English) A rare mauve gemstone with a hexagonal crystal structure.

Taaffeite (; BeMgAlO) is a mineral, named after its discoverer Richard Taaffe (1898–1967) who found the first sample, a cut and polished gem, in October 1945 in a jeweler's shop in Dublin, Ireland. As such, it is the only gemstone to have been initially identified from a faceted stone. Most pieces of the gem, prior to Taaffe, had been misidentified as spinel. For many years afterwards, it was known only in a few samples, and is still one of the rarest gemstone minerals in the world.

Since 2002, the International Mineralogical Association-approved name for taaffeite as a mineral is magnesiotaaffeite-2N'2S.