Taafeite (BeMgAl4O8) is a very rare mineral and often misidentified as spinel. Surprisingly, the gemstone was first discovered already cut and polished in Dublin, Ireland in 1945. At the time the gemstone was mislabelled as spinel and upon further inspection, it was determined that the mineral was actually a new unidentified gem. The primary difference between spinel and taafeite is the double refraction found in the later. The gem is found in alluvial deposits within Sri Lanka and Tanzania.