tanzanite

plural tanzanites

1. countableuncountableA trichroic violet-blue variety of the mineral zoisite mined in Tanzania, used as a gemstone.First known use 1968

   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.

   2012 March–April, Lee A. Groat, “Gemstones”, in American Scientist, volume 100, number 2, New Haven, Conn.: Sigma Xi, the Scientific Research Society, →ISSN, →OCLC, archived from the original on 19 Jul 2023, page 128

   2 more examples

   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.

   1968 October 1, Margene Morris, “Tiffany gets a new home”, in San Francisco Examiner, number 80, San Francisco, Calif.: San Francisco Newspaper Print Co., →ISSN, →OCLC, page 22, column 2

   Last February the new gem was spotted by Harry Platt. […] Just what happened to zoisite in one certain mine in Tanzania, near the Kenya border, nobody knows. Harry Platt bought as many of the freak stones as he could find and had them cut and polished especially for Tiffany. He named the stone tanzanite for its native country. […] None of the Tiffany tanzanites are the same color. They shade from the vivid marine blue of the 48-carat stone to the soft gray blue of a star sapphire. Characteristic of all of them are the purple or green flashes inside the tanzanites when they are held up to the light.

   1968 October 3, Eugenia Sheppard, “Inside Fashion: Something new at Tiffany’s is Tanzanian blue gem”, in Durham Morning Herald, final edition, Durham, N.C.: The Durham Herald Co., →OCLC, section B, page 2B, columns 1–2

   Synonyms: blue zoisite, pleochroic zoisite, vanadium zoisite