tanzanite

noun

1. (countable, uncountable)A trichroic violet-blue variety of the mineral zoisite mined in Tanzania, used as a gemstone.

   “For those to whom gems light the way, a brand new semi-precious stone will be seen for the first time. Called "Tanzanite," the stone was discovered recently in Tanzania. A blue, very much like sapphire, with a slight violet cast, it is exclusive with Tiffany.”

   “Although there are dozens of different types of gems, among the best known and most important are diamond, ruby and sapphire, emerald and other gem forms of the mineral beryl, chrysoberyl, tanzanite, tsavorite, topaz and jade.”