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Tanzanite

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About Tanzanite - History and Introduction

Historical values 2005 - 2016

Color

Color Description; Occurrence

1 ct.

3 ct.

5 ct.

10 ct.

30 ct.

160 - medium violetish Blue; strong

Alternative name, occurrence category: Zoisite. Common

774.66

803.15

831.64

902.87

No data

169 - medium bluish Violet; strong

Alternative name, occurrence category: Zoisite. Common

757.53

785.39

813.25

882.90

No data

158 - medium light violetish Blue; strong

Alternative name, occurrence category: Zoisite. Common

459.97

476.89

493.81

536.10

No data

164 - light bluish Violet; strong

Alternative name, occurrence category: Zoisite. Common

356.56

369.67

382.79

415.57

No data

163 - very light bluish Violet

Alternative name, occurrence category: Zoisite. Common

310.24

321.65

333.07

361.59

No data

146 - light Blue; strong

Alternative name, occurrence category: Zoisite. Common

284.23

294.69

305.14

331.27

No data

129 - light very strongly greenish Blue; very slightly greyish

Alternative name, occurrence category: Zoisite. Common

237.28

246.01

254.74

276.55

No data

069 - medium yellowish Green; slightly greyish (unheated)

Alternative name, occurrence category: Zoisite. Common

260.76

270.35

279.94

303.91

No data

084 - medium light Green; slightly greyish (unheated)

Alternative name, occurrence category: Zoisite. Common

271.54

281.53

291.52

316.48

No data

073 - light slightly yellowish Green; strong (unheated)

Alternative name, occurrence category: Zoisite. Common

255.68

265.09

274.49

298.00

No data

062 - light yellowish Green; strong (unheated)

Alternative name, occurrence category: Zoisite. Common

220.79

228.91

237.03

257.33

No data

045 - light Yellow, very slightly brownish (unheated)

Alternative name, occurrence category: Zoisite. Common

183.36

190.10

196.84

213.70

No data

033 - medium light Orange; very slightly brownish (unheated)

Alternative name, occurrence category: Zoisite. Common

201.75

209.17

216.59

235.15

No data

Tanzanite

Tanzanite is one of the newest gems on the market and was discovered only in 1967 in Tanzania. This lovely gem has been a worldwide success, and demand continues to exceed supply. Tanzanite is a variety of zoisite, which is a member of the epidote group. Colors include blue, purple and green. The most highly coveted colour is a deep blue which shows a purple shimmer.


Tanzanite is trichroic and exhibits pronounced pleochroism. The colors respective to the three directions are sapphire-blue, sage green, and purple. Orientation is an important consideration for cutters who need to consider both the yield and the resulting colour.

Tanzanite is indeed one of the most popular gems, frequently used in gemstone rings, engagement rings - centerstones and as tanzanite melee - and tanzanite is very-well suited for all other types of gemstone jewelry, including gemstone earrings, pins and brooches, as well as in necklaces and fine gemstone pendants.

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Tanzanite

Colour: blue, violet blue, green, yellow, brownish

Hardness: 6,5 - 7

Refractive index: 1.69 - 1.70

Density: 3.35 - 3.38

Chemical composition: Ca2Al3(O/OH/SiO4/Si2O7)

Crystal structure: orthorhombic

Origins: Tanzania

The most valued tanzanites (zoisites) are typically vivid, violet-blue crystals with greenish or orangey stones being rare. Heat treatment is applied to enforce the violet colour component.