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This page kindly sponsored by Lapigems Tanzanite Company
A variety of Zoisite

A gem variety of zoisite with a blue to blue-violet colour.

Note that a significant percentage of tanzanite crystals on the market have been heat-treated (400-500°C) to produce or enhance this colour, many are originally brown or pale grey (Hurlbut 1969; see photo to the right). A red tint seen looking down the c-axis is a good indication that the crystal colouration is natural. Note also that tanzanion is used as a synthetic simulant for tanzanite.
Natural and heat-treated tanzanite is strongly pleochroic (Hurlbut 1969). The photo to the right shows a single crystal viewed from different directions.

First reported from the Merelani Hills (Mererani), Umba Valley, Lelatema Mts, Arusha Region, Tanzania.

Visit for gemological information about Tanzanite.

Classification of Tanzanite URL:
Please feel free to link to this page.

Other Names for Tanzanite

Name in Other Languages:
Norwegian (Bokmål):Tanzanitt

Other Information

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Tanzanite

Reference List:
Hurlbut, C.S., Jr. (1969) Gem zoisite from Tanzania. American Mineralogist: 54: 702-709.

Internet Links for Tanzanite

The following Tanzanite specimens are currently listed for sale on

Localities for Tanzanite

(TL) indicates type locality for a valid mineral species. (FRL) indicates first recorded locality for everything else. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
No reference listed
  • Manyara Region
    • Simanjiro District
      • Lelatema Mts
        • Merelani Hills (Mererani)
Wilson, W.E., Saul, J.M. Pardieu, V. & Hughes R.W. (2009): Famous Mineral Localities. The Merelani Tanzanite Mines, Lelatema Mountains, Arusha Region, Tanzania. Mineralogical Record, 40: 347-408.
Wilson, W.E., Saul, J.M. Pardieu, V. & Hughes R.W. (2009): Famous Mineral Localities. The Merelani Tanzanite Mines, Lelatema Mountains, Arusha Region, Tanzania. Mineralogical Record, 40: 347-408.
Min Rec (2009) 40:347-408
Olivier, Bernard (2008): The geology and petrology of the Merelani tanzanite deposit, NE Tanzania. Doctoral thesis, University of Stellenbosch, South Africa.
Andy Seibel
Natural HistoryMuseum of Los Angeles Co.specimen catalogue No. 41249.
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