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INVESTIGATIONS

Stone

RI min

RI max

Dens min

Dens max

Colour

Location

Info

Spectrum

UVS

UVL

Reference

Andradite

1.85

1.87

3.72

3.89

green-yellow, bluish green, brown

Anbanja, Madagascar

chelsea : red; strongly magnetic; 1.85ct-3.89ct

 

inert

inert

Revue de  Gemmologie A.F.G. 2009 Sep p6-10

Andradite

1.851

1.888

3.77

3.85

emerald green, orange-brown, green-brown (topazolite), yellow, pale yellow-green (greenfire), black (melanite), yellowish brown (golden cat's eye)

San Benito County, California

translucent to opaque

 

inert

inert

Gems & Gemology 1981 fall p157-160

Demantoid - andradite

 

 

3.77

3.85

yellowish green to emerald green

Pakistan

 

 

 

 

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2001 Mar, p5156

Demantoid - andradite

 

 

3.79

3.88

olive-green, emerald-green

Anbanja, Madagascar

 

no Cr lines, cut-off in the blue, diffuse bands at 621 and 640nm

 

 

Gems & Gemology 2009 Fall, p218

Andradite

 

 

3.79

3.9

yellow-green to bluish green, greenish-brown, brown

Antetezambato, Ambanja, Madagascar

demantoid and topazolite; demantoid contains very low Cr and V; green colour appears related to Fe³+

 

inert

inert

Gems & Gemology 2011 Spring, p2-14

Andradite

1.86

1.86

3.79

3.79

brown-orange with distinct zones of green

Iran

1.25 ct

 

 

 

Gems & Gemology 2007 Spring, p65-66

Andradite

1.881

1.881

3.8

3.8

brownish yellow

San Benito County, California, USA

 

 

 

 

Gems & Gemology 1983 Winter, p202-208

Demantoid - andradite

 

 

3.81

3.88

yellowish green to green, medium to dark

Val Malenco, Italy

transparent

UV-Vis-Nir:toatal absorption >390nm, strong bands 435-440, broad feature at 480nm, absorptions 575,620,640, doublet 695-700, broad band at 860nm

inert

inert

Gems & Gemology 2009 Winter, p 280-287

Demantoid - andradite

1.88

1.883

3.81

3.87

yellow-green

Russia

10 stones

 

 

 

Gems & Gemology 1983 Winter, p202-208

Demantoid - andradite

 

 

3.82

3.82

green, light yellow, orange, light orange, brownish orange

Kerman Province, Iran

often magnetic

strong band at 443, two bands at 622 and 640

 

 

Gems & Gemology 2006 fall p131

Andradite

 

 

3.82

3.93

orangy brown, brownish yellow

Erzincan, eastern Turkey

0.15 - 0.38 ct

440 nm cutoff

inert

inert

Gems & Gemology 2009 Summer, p142

Demantoid - andradite

1.889

1.889

3.82

3.82

yellow-green

Korea

 

 

 

 

Gems & Gemology 1978 Winter, p123-124

Andradite

 

 

3.83

3.88

brownish yellow, brownish yellow green, yellowish green, brownish orange, brown-red

28 km NE of Klein Spitzkoppe, Namib desert, Namibia

 

cutoff at 460  or 520, weak Cr (only in demantoid)

inert

inert

Gems & Gemology 2007 winter , p370-371

Demantoid - andradite

 

 

3.83

3.86

yellowish green, green

Kerman District, Iran

0.38-1.23 carat

fibers, horse tail

 

 

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2003 Mar, p3

Andradite

 

 

3.83

3.83

iridiscent colours

Buffelsfontein, North West Province, South Africa

16.02ct, opaque, cabochon

broad absorption below 490nm

inert

inert

GIA Gem Database  33282

Demantoid - andradite

 

 

3.83

3.85

green to yellowish green

Namibia

0.71 - 3.42 ct, strong anomalous double refraction, RI OTL, chelsea: orange to red

band at 445 nm, general absorption below 450 nm

inert

inert

Gems & Gemology 1997 Fall, p222-223

Demantoid - andradite

1.88

1.88

3.83

3.94

yellowish green

Black Lake, Quebec, Canada

 

 

 

 

Canadian Gemmologist 1999 Mar, p18-19

Demantoid - andradite

1.881

1.881

3.84

3.84

 

 

1.45ct, composition: Adr96Grs4

 

 

 

Gems & Gemology 2011 Winter, p274

Demantoid - andradite

 

 

3.84

3.84

green

 

5.82ct

chrome lines and a 470 nm
cutoff

 

 

Gems & Gemology 2006 winter, p 261-262

Demantoid - andradite

 

 

3.85

3.85

 

Antetezambato, Ambanja, Madagascar

0.86 ct

 

 

 

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2009 58/3-4/Dec, p80-81

Demantoid - andradite

 

 

3.85

3.85

yellowish green

Kerman, Kerman Province, Iran

1.67ct

broad absorption below 460nm

inert

inert

GIA Gem Database  35637

Demantoid - andradite

 

 

3.85

3.95

yellow-green to green

northern Pakistan

0.30 - 0.60 ct

a strong broad absorption band at 440 nm and lines in the red

inert

inert

Gems & Gemology 2005 Summer, p176

Demantoid - andradite

1.88

1.883

3.85

3.88

yellow-green

Italy

9 stones

 

 

 

Gems & Gemology 1983 Winter, p202-208

Demantoid - andradite

 

 

3.86

3.86

yellowish green

 

4.31ct

broad absorption below 440nm

inert

inert

GIA Gem Database  33301

Demantoid - andradite

 

 

3.86

3.87

yellowish green

Bobravka River, near Nizhniy Tagil, Russia

IR OTL, 1.18 and 1.34ct, chelsea: deep orangy red, "horsetails" inclusions

460 nm cutoff, 620 nm, line, 638 nm line, weak 690 nm line, 680 nm cutoff

inert

inert

Gems & Gemology 1997 Fall, p222

Andradite

 

 

3.86

3.86

very dark red

Namibia

5.73ct, RI OTL

a 420 nm cutoff

inert

inert

Gems & Gemology 2001 Spring, p 56

Demantoid - andradite

 

 

3.86

3.89

yellowish green to green, medium to dark

Iran

0.12 - 1.13 ct, RI OTL

Cr doublet (620 and 640 nm)

inert

inert

Gems & Gemology 2002 Spring, p96

Andradite

 

 

3.87

3.94

brownish yellow-orange to yellowish orange-brown

Baluchistan, Pakistan

 

absorption at 500nm

inert

inert

Gems & Gemology 2007 winter , p373

Demantoid - andradite

 

 

3.87

3.87

yellowish green

 

4.24ct

broad absorption below 450nm

inert

inert

GIA Gem Database  33303

Demantoid - andradite

1.882

1.882

3.87

3.87

 

 

1.79ct, composition: Adr90Uv7Grs9

 

 

 

Gems & Gemology 2011 Winter, p274

Andradite

 

 

3.91

3.91

green-yellow to greenish yellow-brown

China

0.30 - 1.58ct

strong absorption below 450 nm

inert to weak red

inert to very weak red

Gems & Gemology 2010 Spring, p59

Demantoid - andradite

1.84

1.84

3.92

3.92

green

Anbanja, Madagascar

0.83ct

 

inert

inert

ACAM lab  2115

Andradite

 

 

3.92

3.92

brownish greenish yellow to yellow-brown

Arizona, USA

0.10 - 1.51ct

line at 440 nm

 

 

Gems & Gemology 1997 Spring, p61

Demantoid - andradite

1.84

1.84

3.93

3.93

 

Sri Lanka

magnetic, chelsea: pink; 0.29ct

 

 

 

http://www.geminterest.com 2007

Andradite

 

 

4.17

4.43

yellow-green, and yellowish green

Erzincan, eastern Turkey

 

440 nm cutoff

inert

inert

Gems & Gemology 2009 Summer, p142

Demantoid - andradite

1.89

1.89

 

 

yellowish or brownish green to golden green, emerald green

 

 

 

 

 

Gems & Gemology 1996 summer p100-111

Andradite

 

 

 

 

rainbow andradite, probably caused by combination of a narrowly spaced lamellar structure following the rhombic dodecahedron {110}and an other wavy, widely spaced, step like lamellar structure not // to {110}

Nara , Japan

 

 

 

 

Gems & Gemology 2006 winter, p 248

 

TABLES

Stone

RI min

RI max

Dens min

Dens max

Reference

Andradite

1.84

1.94

3.7

4.1

http://www.geminterest.com 

Andradite

1.84

1.888

3.76

3.87

Gemmo.eu 

Andradite

1.855

1.895

3.81

3.87

Bestimmungstabellen für Edelsteine, Birgit Günther, 1981 

Andradite

1.855

1.94

3.68

4.1

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

Demantoid - andradite

1.855

1.895

3.8

3.87

Tabellen zur Edelstein-Bestimmung, Pschichholz FGA, 1975 

Andradite

1.855

1.895

3.81

3.87

Gemology Tools Professional 2010

Demantoid - andradite

1.855

1.895

3.81

3.87

Gemology Tools Professional 2010

Demantoid - andradite

1.86

1.89

3.83

3.8

John Sinkakas, Gemstone and mineral data book,1972 

Andradite

1.87

1.935

3.82

3.94

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

Andradite

1.88

1.94

3.7

4.1

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Demantoid - andradite

1.88

1.889

3.77

3.88

Gemmological Tables, Ulrich Henn, 2004 

Andradite

1.88

1.935

3.82

3.9

http://www.gemmology.be 

Demantoid - andradite

1.88

1.888

3.82

3.91

http://www.geminterest.com 

Demantoid - andradite

1.881

1.888

3.82

3.88

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Demantoid - andradite

1.881

1.888

3.82

3.91

http://www.geminterest.com 

Demantoid - andradite

1.885

1.9

3.81

3.88

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

Demantoid - andradite

1.89

1.89

3.82

3.85

Gems, R Webster, 5th edition 1994 

Andradite

 

 

3.8

3.9

John Sinkakas, Gemstone and mineral data book,1972 

 

CAUSE OF COLOUR

stone

colour

cause of colour

reference

Andradite

black

charge-transfer Fe²+-O-Ti4+

Mr. Dominique Flies, La couleur des grenats, l’Université de Nantes, 2008

Andradite - demantoid

green

Cr³+ in octahedral coordination

Mr. Dominique Flies, La couleur des grenats, l’Université de Nantes, 2008

Andradite

multicolours

diffraction

Gems & Gemology Summer 1988

Andradite

yellow

various charge-transfer processes and dispersed ion absorption involving Fe and Ti

Gems & Gemology Summer 1988

Andradite

yellow

charge-transfer Fe²+-O-Ti4+

Mr. Dominique Flies, La couleur des grenats, l’Université de Nantes, 2008

Andradite

yellow-brown

Fe³+ in octahedral coordination and charge-transfer Fe²+-O-Ti4+

Rondeau et al, 2009 (www.geminterest.com)

Andradite

yellow-green

Fe³+ in octahedral coordination

Gems & Gemology Summer 1988

 

MINERAL INCLUSIONS

Inclusion

Stone

Reference

antigorite

andradite - demantoid

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

calcite

andradite

Gems & gemology spring 2007 Spring p 65

chromite

andradite - demantoid

Gem & Gemology, Volume 32, Number 2 / Summer 1996

chrysotile

andradite - demantoid

Gemmological Tables, Ulrich Henn , GGA, 2004

diopside

andradite - demantoid

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

magnetite

andradite - demantoid

Gems & Gemology 2014, Winter, p302-303

pyrite

andradite - demantoid

Gems & Gemology 2011, Spring, p8

sphalerite

andradite - demantoid

Gems & Gemology 2016, Winter, p422

wollastonite

andradite - demantoid

Gems & Gemology 2011, Spring, p8

 

LOCALITIES

Andradite-demantoid

Black Lake

Mégantic County

Quebec

Canada

InColor- Winter 2007/2008

Andradite-demantoid

Soghan

Jeroft

Kerman

Iran

Mineralogical Record 3/2002

Andradite-demantoid

Sferlun, Vallone del Cengiask

Malenco Valley

Sondrio Province, Lombardia

Italy

I Minerali della Provincia di Sondrio, F. Bedogné,1993

Andradite

Kohse mine, Tenkawa village, Yoshino-gun, Nara Prefecture

Kinki Region

Honshu Island

Japan

N. Shimobayashi, et al. (2005) Rainbow garnet from Tenkawa village in Nara.

Andradite-demantoid

Ambanja District

Diana (Northern) Region

Antsiranana Province

Madagascar

Gems & Gemology 2009 Fall p218

Andradite-demantoid

Antetezambato (Tetezambato), Ambanja District

Diana (Northern) Region

Antsiranana Province

Madagascar

Pezzotta, F. (2009). Rivista Mineralogica Italiana, n.3-2009, 198-200.

Andradite-demantoid

28km NE of Klein Spitzkopje

Swakopmund

Damaraland

Namibia

Gems & Gemology 2007 winter, p 371

Andradite-demantoid

Green Dragon Mine, Tubussis Farm 22 (Tubussis; Tubusis; Tubessis)

Karibib District

Erongo Region

Namibia

Gems & Gemology Summer 2015, p210-211

Andradite-demantoid

Tubussis 22 farm

Karibib District

Erongo Region

Namibia

Namibia, Zauberwelt edler Steine und Kristalle, Steffen Jahn e.a., 2001

Andradite

 

 

Balochistan (Baluchistan)

Pakistan

Gems & Gemology 2007, winter p373

Andradite-demantoid

Kladovka Mine

Nizhnii Tagil, Sverdlovskaya Oblast'

Urals Region

Russia

Gems & Gemology 2003 spring p54

Andradite-demantoid

Sysert' District

Sverdlovskaya Oblast'

Urals Region

Russia

Gems & Gemology Summer 1996

 

CHEMICAL DATA

Stone

Colour

Locality

Reference

SiO2

Al2O3

MnO

MgO

FeO

TiO2

CaO

Na2O

Cr2O3

V2O3

Fe2O3

Andradite

slightly yellowish green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.7

 

 

 

 

 

33.49

 

 

 

31.35

Andradite

yellowish green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.43

 

 

0.07

 

 

33.58

 

 

 

31.26

Andradite

yellow-green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.47

 

 

0.11

 

 

33.41

 

 

 

31.07

Andradite

yellow-green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.61

 

 

0.12

 

 

33.48

 

 

 

31.01

Andradite

yellow-green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.39

 

 

 

 

0.05

33.44

 

 

 

31.09

Andradite

yellowish green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.53

 

 

0.06

 

0.03

33.46

 

0.18

 

30.87

Andradite

yellowish green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.83

 

 

 

 

0.03

33.45

 

 

 

30.97

Andradite

yellow-green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.33

0.1

 

0.24

 

0.09

33.66

 

 

 

30.56

Andradite

yellow-green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.27

 

 

0.07

 

0.09

33.28

 

0.06

 

30.68

Andradite

yellowish green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.59

 

 

0.07

 

 

33.35

 

0.1

 

31.12

Andradite

yellowish green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.66

 

 

 

 

0.04

33.38

 

 

 

30.93

Andradite

greenish-yellow

 

Italy

The Journal of Gemmology 2007,30,5/6,307-319

34.87

0.1

0.02

0.17

0.02

0.05

33.02

 

0.02

 

31.3

Andradite

yellow-green

 

Italy

Gems & Gemology 1983 Winter p204-205

35.46

 

 

 

 

0

33.37

 

0.16

 

30.74

Andradite - demantoid

yellowish green

Val Malenco

Italy

Gems & Gemology 2009 Winter, p284

35.37

0.07

0.03

0.13

 

0.01

33.04

0.01

0.03

 

31.6

Andradite - demantoid

yellowish green

Val Malenco

Italy

Gems & Gemology 2009 Winter, p284

35.95

0.06

0.01

0.1

 

0.02

33.04

0.01

 

 

31.6

Andradite - demantoid

green

Val Malenco

Italy

Gems & Gemology 2009 Winter, p284

35.93

0.15

0.02

0.15

 

0.01

33.06

0.01

0.18

 

31.05

Andradite - demantoid

green

Val Malenco

Italy

Gems & Gemology 2009 Winter, p284

35.76

0.06

0.02

0.13

 

0.04

33.02

 

0.19

 

31.27

Andradite - demantoid

green

Val Malenco

Italy

Gems & Gemology 2009 Winter, p284

35.73

0.08

0.03

0.17

 

0.05

32.98

 

0.29

 

30.98

Andradite - demantoid

green

Val Malenco

Italy

Gems & Gemology 2009 Winter, p284

35.81

0.05

0.04

0.11

 

0.02

33.04

 

0.58

 

31.01

Andradite - demantoid

yellowish green

Val Malenco

Italy

Gems & Gemology 2009 Winter, p284

35.39

0.08

0.03

0.12

 

0.03

33.04

0.01

0.01

 

31.51

Andradite - demantoid

green

Val Malenco

Italy

Gems & Gemology 2009 Winter, p284

35.88

0.06

0.02

0.09

 

0.03

32.99

 

0.47

 

31.07

Andradite

bluish green

Antetezambato

Madagascar

Gems & Gemology 2011, Spring, p9

35.47

0.01

0.01

0.07

 

0.01

33.24

 

 

 

31.93

Andradite

green

Antetezambato

Madagascar

Gems & Gemology 2011, Spring, p9

34.73

0.01

0.01

0.08

 

 

32.93

 

 

 

31.42

Andradite

yellowish-green

Antetezambato

Madagascar

Gems & Gemology 2011, Spring, p9

35.57

0.06

0.01

0.15

 

0.01

33.16

 

 

 

31.55

Andradite

brown

Antetezambato

Madagascar

Gems & Gemology 2011, Spring, p9

35.52

0.02

0.01

0.06

 

 

32.84

 

 

 

31.23

Andradite

brown

 

Mali

Gems & Gemology Fall 1995 p 163

36.43

6.29

0.1

0.34

 

1.18

34.42

 

 

0.04

20.91

Andradite - demantoid

green

 

Pakistan

Gemmologie, Zeitschrift der deutschen gemmologischen Gesellschaft, 2001, Mar, p53

35.04

0.16

 

 

0.04

0.04

33.63

 

0.15

 

31.04

Andradite

slightly yellowish green

 

Russia

Gems & Gemology 1983 Winter p204-205

35.51

 

 

 

 

 

33.5

 

 

 

31.13

Andradite

slightly yellowish green

 

Russia

Gems & Gemology 1983 Winter p204-205

35.63

 

 

0.07

 

 

33.38

 

 

 

30.83

Andradite

yellowish green

 

Russia

Gems & Gemology 1983 Winter p204-205

35.87

 

 

 

 

 

33.42

 

 

 

31.22

Andradite

yellow-green

 

Russia

Gems & Gemology 1983 Winter p204-205

35.72

 

 

 

 

 

33.62

 

 

 

31.1

Andradite

yellowish green

 

Russia

Gems & Gemology 1983 Winter p204-205

35.72

 

 

 

 

 

33.52

 

 

 

31.08

Andradite

yellow-green

 

Russia

Gems & Gemology 1983 Winter p204-205

35.27

 

 

 

 

 

33.51

 

 

 

31.14

Andradite

yellowish green

 

Russia

Gems & Gemology 1983 Winter p204-205

35.62

 

 

0.09

 

0.03

33.38

 

 

 

31.02

Andradite

slightly orangy yellow

San Benito County, California

USA

Gems & Gemology 1983 Winter p204-205

35.56

 

0.07

 

 

 

33.29

 

 

 

30.52

Andradite

yellowish brown

San Benito County, California

USA

Gems & Gemology 1981 Fall p158

36.88

0.44

0.09

0.27

 

0.33

33.3

 

0.3

0.02

28.37

Andradite - demantoid

green

San Benito County, California

USA

Gems & Gemology 1981 Fall p158

36.03

0.06

0.01

0.03

 

0.02

33.09

 

0.97

0.04

29.75