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INVESTIGATIONS

Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

Colour

Locality

Info

nx min

nx max

ny min

ny max

nz min

nz max

Spectrum

UVS

UVL

Reference

Zoisite

1.688

1.7

0.008

0.01

3.35

3.37

bluish green to yellowish green

Merelani Hills, Tanzania

 

 

 

 

 

 

 

broad absorption of the violet and most of the blue, weak to distinct bands at 660 and 680nm

inert

inert

Gems & Gemology 1992 spring p4-15

Tanzanite - zoisite

1.689

1.7

0.011

0.011

3.37

3.37

violetish blue

 

0.39 - 0.82 ct, colour coated with titanium

 

 

 

 

 

 

 

 

 

Gems & Gemology 2014 Spring, p71

Zoisite

1.69

1.7

0.01

0.01

3.44

3.44

brown

 

biaxial +

 

 

 

 

 

 

 

 

 

ACAM labo 

Zoisite

1.69

1.7

 

 

3.37

3.37

bicoloured: pink and yellow

 

1.62 and 4.30 ct

 

 

 

 

 

 

band at 455nm

inert

very weak yellow

Gems & Gemology 2000 Summer, p159

Tanzanite - zoisite

1.69

1.69

 

 

3.38

3.38

 medium dark greyish violet-blue

 

2.69ct, cabochon cat's-eye, RI by spot, chatoyancy caused by channels

 

 

 

 

 

 

 

inert

inert

The Journal of Gemmology 1991 Vol 22, N°7, p397

Tanzanite - zoisite

1.691

1.7

0.009

0.009

3.33

3.33

blue

Tanzania

1.92ct

1.691

1.691

1.695

1.695

1.700

1.700

 

inert

inert

ACAM lab  2163

Zoisite

1.694

1.702

0.008

0.008

3.33

3.37

very light brownish purple

Shinwari tribal area, Nangarhar Province, Afghanistan

 

1.694

1.694

1.695

1.695

1.702

1.702

427nm and 452nm lines

inert

inert

Gems & Gemology 2009 spring p 70

Zoisite

1.695

1.703

0.008

0.008

3.35

3.35

greenish yellow

 

8.33 ct

 

 

 

 

 

 

none

inert

inert

The Australian Gemmologist 2010 Vol 24, N°4,p90-91

Zoisite

1.695

1.7

0.005

0.005

3.36

3.36

dark yellowish green

Merelani Hills, Lelatema Mts, Arusha Region, Tanzania

6.11ct

 

 

 

 

 

 

 

inert

inert

GIA Gem Database  35522

Tanzanite - zoisite

1.695

 

 

 

3.36

3.36

bluish violet

Tanzania

11.98ct, biaxial +

 

 

 

 

 

 

 

inert

inert

GIA Gem Database  34128

Zoisite

1.701

1.707

 

 

3.38

3.38

brownish yellow-green

Alchuri, Pakistan

 

 

 

 

 

 

 

absorption at 430nm and 450nm

inert

inert

Gems & Gemology 2012 Fall, p230

 

TABLES

Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

nx min

 nx max

ny min

ny max

nz min

nz max

Reference

Zoisite

1.685

1.725

0.004

0.01

3.15

3.38

1.685

1.705

 

 

1.697

1.725

Gemme, Dati per l'identificazione, P. De Stefano et al, 1993 

Zoisite

1.685

1.725

0.004

0.008

3.15

3.38

 

 

 

 

 

 

http://www.gemmology.be 

Zoisite

1.685

1.725

0.004

0.008

3.15

3.38

1.685

1.705

1.688

1.710

1.697

1.725

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Zoisite

1.685

1.725

0.004

0.013

3.1

3.45

1.685

1.705

1.688

1.710

1.697

1.725

http://www.geminterest.com 

Zoisite

1.685

1.725

0.004

0.012

3.15

3.55

1.685

1.705

1.688

1.710

1.697

1.725

Tables of Gemstone Identification, Roger Dedeyne, Ivo Quintens, 2007 

Zoisite

1.685

1.725

0.004

0.008

3.1

3.45

 

 

 

 

 

 

Gemology Tools Professional 2010

Tanzanite - zoisite

1.686

1.705

0.008

0.013

3.1

3.6

 

 

 

 

 

 

Gemology Tools Professional 2010

Tanzanite - zoisite

1.69

1.709

0.006

0.012

3.23

3.55

1.690

1.700

 

 

1.699

1.709

Gemme, Dati per l'identificazione, P. De Stefano et al, 1993 

Tanzanite - zoisite

1.69

1.706

0.008

0.013

3.34

3.43

1.690

1.700

1.693

1.693

1.698

1.706

http://www.geminterest.com 

Tanzanite - zoisite

1.69

1.702

0.006

0.012

3.33

3.36

 

 

 

 

 

 

Tables of Gemstone Identification, Roger Dedeyne, Ivo Quintens, 2007 

Zoisite

1.69

1.706

0.006

0.01

3.25

3.55

1.690

1.700

 

 

1.700

1.706

Bestimmungstabellen für Edelsteine, Birgit Günther, 1981 

Zoisite

1.69

1.707

0.008

0.009

3.2

3.5

1.690

1.700

1.693

1.703

1.698

1.707

Gemmological Tables, Ulrich Henn, 2004 

Tanzanite - zoisite

1.691

1.7

0.009

0.009

3.35

3.35

 

 

 

 

 

 

http://www.gemmology.be 

Zoisite

1.691

1.7

0.008

0.008

3.12

3.37

 

 

 

 

 

 

John Sinkakas, Gemstone and mineral data book,1972 

Zoisite

1.691

1.706

1.691

1.706

3.1

3.4

1.691

1.700

 

 

1.700

1.706

Tabellen zur Edelstein-Bestimmung, Pschichholz FGA, 1975 

Zoisite

1.691

1.702

0.008

0.01

3.05

3.43

 

 

 

 

 

 

Gemmo.eu 

Tanzanite - zoisite

1.692

1.7

0.009

0.009

3.35

3.35

1.692

1.692

1.693

1.693

1.700

1.700

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Zoisite

1.692

1.7

0.008

0.008

3.35

3.35

 

 

 

 

 

 

Gems, R Webster, 5th edition 1994 

Thulite - zoisite

1.695

1.701

0.006

0.006

3.09

3.09

 

 

 

 

 

 

http://www.gemmology.be 

Thulite - zoisite

1.695

1.701

0.006

0.006

3.09

3.09

1.695

1.695

 

 

1.701

1.701

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Thulite - zoisite

1.695

1.701

0.006

0.006

3.09

3.1

1.695

1.695

1.696

1.697

1.701

1.701

http://www.geminterest.com 

Thulite - zoisite

1.695

1.701

0.006

0.006

3.09

3.09

 

 

 

 

 

 

Tables of Gemstone Identification, Roger Dedeyne, Ivo Quintens, 2007 

Thulite - zoisite

1.695

1.701

0.006

0.006

3.09

3.09

 

 

 

 

 

 

Gemology Tools Professional 2010

Thulite - zoisite

1.7

1.71

 

 

3.25

3.27

 

 

 

 

 

 

John Sinkakas, Gemstone and mineral data book,1972 

Thulite - zoisite

1.7

1.706

0.006

0.006

3.09

3.12

 

 

 

 

 

 

Gems, R Webster, 5th edition 1994 

Thulite - zoisite

 

 

 

 

3.1

3.37

 

 

 

 

 

 

Gemme, Dati per l'identificazione, P. De Stefano et al, 1993 

 

CAUSE OF COLOUR

Stone

Colour

Cause of colour

Reference

Tanzanite - zoisite

blue

V4+ in octahedral coordination; with V³+  in octahedral coordination

Gems & Gemology Summer 1988

Zoisite

brown-violet

V³+  in octahedral coordination

Gems & Gemology Summer 1988

Zoisite

green

Cr and V

Gems & Gemology 1992 Spring p4-15

Thulite - zoisite

pink

Mn³+ in presumably octahedral coordination

Gems & Gemology Summer 1988

 

MINERAL INCLUSIONS

Inclusion

Stone

Reference

graphite

Tanzanite - zoisite

E.J. Gübelin and J.I. Koivula, Photoatlas of inclusions in Gemstones, volume 2 (2005)

hematite

Zoisite

The Journal of Gemmology 1995, 24,8, p577

zircon

Tanzanite - zoisite

E.J. Gübelin and J.I. Koivula, Photoatlas of inclusions in Gemstones, volume 2 (2005)

 

LOCALITIES

STONE

LOCALITIES

REFERENCE

Zoisite

 

Shinwari tribal area

Nangarhar (Ningarhar) Province

Afghanistan

Gems & Gemology Spring 2009 p70

Zoisite

Alchuri

Shigar Valley

Baltistan

Pakistan

Gems & Gemology Fall 2010, p215

tanzanite-Zoisite

Merelani Hills, Umba Valley

Lelatema Mts

Arusha region

Tanzania

Lapis 1997/9

Zoisite

 

Longido

Kilimanjaro Region

Tanzania

Gemmologie, 1997, Mar,p31

 

CHEMICAL DATA (%)

Stone

Colour

Locality

Reference

SiO2

Al2O3

MnO

MgO

FeO

TiO2

CaO

Na2O

Cr2O3

V2O3

Ga2O3

ZnO

Fe2O3

K2O

H2O

SrO

Zoisite

medium green

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.82

32.89

0.02

0.09

 

0.04

23.91

 

0.3

0.07

0.03

0.02

0.01

 

 

0.27

Zoisite

dark green

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.61

33.41

 

0.03

 

0.03

24.01

 

0.16

0.09

0.01

0.01

0.01

 

 

0.26

Zoisite

dark bluish green

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.8

33.23

0.01

0.06

 

0.06

23.93

 

0.26

0.06

0.03

0.02

0.01

 

 

0.27

Zoisite

medium bluish green

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.76

33.11

0.01

0.05

 

0.03

24.15

 

0.17

0.1

0.03

0.01

 

 

 

0.27

Zoisite

medium bluish green

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.49

33.01

0.01

0.02

 

0.01

24.02

 

0.13

0.09

0.02

 

 

 

 

0.35

Zoisite

medium yellow green

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

38.91

33.25

0.01

0.05

 

0.04

23.91

 

0.09

0.11

0.04

 

0.01

 

 

0.23

Zoisite

medium yellow green

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.1

33.24

 

0.04

 

0.03

24

 

0.11

0.17

0.01

0.01

 

 

 

0.06

Zoisite

light yellow green

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.59

33.34

 

0.04

 

0.01

24.25

 

0.09

0.16

0.02

0.01

0.01

 

 

0.14

Zoisite

medium slightly greenish blue (heated)

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.58

33.25

0.01

0.05

 

0.05

24.16

 

0.12

0.13

0.03

 

0.01

 

 

0.21

Zoisite

medium slightly greenish blue (heated)

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

38.3

33.24

0.01

0.04

 

0.02

23.98

 

0.11

0.16

0.01

0.02

0.01

 

 

0.13

Zoisite

medium blue

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.89

33.2

 

0.05

 

0.03

23.88

 

0.05

0.16

0.03

0.01

0.02

 

 

0.54

Zoisite

medium violet blue

Merelani Hills

Tanzania

Gems & Gemology 1992 Spring p13

39.02

33.42

0.02

0.05

 

0.04

24.12

 

0.04

0.16

0.03

0.01

0.01

 

 

0.09

Zoisite

cat's eye

 

East Africa

The Journal of Gemmology 1995, Vol 24, N°8, p 574

40.1

33.4

0.04

0.14

1.11

0.05

23.5

0.1

 

 

 

 

 

 

1.1

0

Zoisite

cat's eye

 

East Africa

The Journal of Gemmology 1995, Vol 24, N°8, p 574

41.1

32.47

0.04

0.15

0.05

0.09

23.91

0.74

 

 

 

 

 

0.21

1.13

0

Zoisite

cat's eye

 

East Africa

The Journal of Gemmology 1995, Vol 24, N°8, p 574

41.76

32.95

0.05

0.17

0.07

0.14

24.01

0.53

 

 

 

 

 

0.2

0.14

0