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Tanzanite
A variety of Zoisite
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About Tanzanite
Formula:
(CaCa)(AlAlAl)O[Si2O7][SiO4](OH)
Name:
Named after the country of Tanzania.
A gem variety of zoisite with a blue to blue-violet colour. The colour is due to the incorporation of trace amounts of vanadium cations (V4+ absorption band increased at 380 nm, V3+ absorption band at 350 nm decreased with heating).
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), Tanzania.
Visit gemdat.org for gemological information about Tanzanite.
First reported from the Merelani Hills (Mererani), Tanzania.
Visit gemdat.org for gemological information about Tanzanite.Unique Identifiers
Mindat ID:
3885 (as Tanzanite)
4430 (as Zoisite)
4430 (as Zoisite)
Long-form identifier:
mindat:1:1:3885:6 (as Tanzanite)
mindat:1:1:4430:7 (as Zoisite)
mindat:1:1:4430:7 (as Zoisite)
Similar Names
| Tinzenite | A valid IMA mineral species | Ca2Mn42+Al4[B2Si8O30](OH)2 |
| Tonsonite | A synonym of Thomsonite-Ca |
Pronunciation of Tanzanite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Chemistry of Tanzanite
Mindat Formula:
(CaCa)(AlAlAl)O[Si2O7][SiO4](OH)
Element Weights:
Synonyms of Tanzanite
Other Language Names for Tanzanite
Dutch:Tanzaniet
Finnish:Tansaniitti
French:Tanzanite
Hebrew:טנזניט
Japanese:タンザナイト
Lithuanian:Tanzanitas
Norwegian:Tanzanitt
Polish:Tanzanit
Portuguese:Tanzanite
Spanish:Tanzanita
Tanjeloffita
Tanjeloffita
Swahili:Tanzanaiti
Swedish:Tanzanit
Common Associates
Associations Based on Photo Data:
| 86 photos of Tanzanite associated with Graphite | C |
| 83 photos of Tanzanite associated with Prehnite | Ca2Al2Si3O10(OH)2 |
| 45 photos of Tanzanite associated with Calcite | CaCO3 |
| 27 photos of Tanzanite associated with Diopside | CaMgSi2O6 |
| 19 photos of Tanzanite associated with Quartz | SiO2 |
| 16 photos of Tanzanite associated with Chabazite | |
| 14 photos of Tanzanite associated with Alabandite | MnS |
| 12 photos of Tanzanite associated with Fluorite | CaF2 |
| 11 photos of Tanzanite associated with Pyrite | FeS2 |
| 10 photos of Tanzanite associated with Apophyllite Group | AB4[Si8O20]X · 8H2O |
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.
Internet Links for Tanzanite
mindat.org URL:
https://www.mindat.org/min-3885.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Tanzanite
Reference List:
HARRIS, C., HLONGWANE, W., GULE, N., SCHEEPERS, R. (2014) Origin of tanzanite and associated gemstone mineralization at Merelani, Tanzania. South African Journal of Geology, 117 (1). 15-30 doi:10.2113/gssajg.117.1.15
Cairncross, Bruce (2020) The Where of Mineral Names: Tanzanite, A Variety of Zoisite, Merelani Hills, Simanjiro District, Manyara Region, Tanzania. Rocks & Minerals, 95 (5). 458-462 doi:10.1080/00357529.2020.1771156
Bačík, Peter, Wildner, Manfred, Cempírek, Jan, Škoda, Radek, Cibula, Peter, Vaculovič, Tomáš (2023) The position of vanadium in the crystal structure of zoisite, variety tanzanite: Structural refinement, optical absorption spectroscopy and bond-valence calculations. Mineralogical Magazine, 87 (4) 599-610 doi:10.1180/mgm.2023.48
Localities for Tanzanite
Showing 10 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
China | |
| Yang et al. (2023) |
Tanzania | |
| Bindi +3 other references |
| Wilson et al. (2009) | |
| Wilson et al. (2009) | |
| Wilson et al. (2009) | |
| Olivier (2008) +1 other reference | |
| Andy Seibel | |
| Natural HistoryMuseum of Los Angeles ... | |
| Mason (1976) |
Merelani Hills, Lelatema Mountains, Simanjiro District, Manyara Region, Tanzania