Taaffeite is a mineral, named after its discoverer Richard Taaffe 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. Wikipedia

Crystal system: Hexagonal

Crystal habit: Prismatic, alluvial grains

Mohs scale hardness: 8–8.5

Optical properties: Uniaxial

Refractive index: n_ω = 1.722, n_ε = 1.777