Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

Colour

Info

ne min

ne max

no min

no max

Spectrum

UVS

UVL

Reference

Synthetic corundum

1,759

1,767

0,008

0,008

3,99

4,04

reddish orange

weak pinkish-red

strong orange-red

The Journal of Gemmology 1985 Vol 19, No 5 p389-403

Synthetic corundum

1,759

1,768

0,009

0,009

3,99

4

medium light pink to medium purplish pink

468.5, 475-476.5 doublet, 659.2, 668, 692.8, 694.2nm

strong orange-red

strong orange-red

The Journal of Gemmology 1994 Vol 24, N°3, p149-154

Synthetic corundum

1,759

1,776

0,007

0,008

3,98

4

red

hydrothermal

1,765

1,769

1,773

1,776

weak reddish

reddish

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2003 Mar, p31-36

Synthetic corundum

1,759

1,771

0,008

0,008

4,02

4,02

violet-blue

hydrothermal

1,759

1,763

1,767

1,771

very weak reddish

weak reddish

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2003 Mar, p31-36

Synthetic corundum

1,759

1,77

0,009

0,01

3,98

3,98

light greenish-blue

hydrothermal

1,759

1,760

1,768

1,770

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2003 Mar, p31-36

Synthetic corundum

1,759

1,768

0,009

0,009

4

4

orange

hydrothermal

weak orange

orange

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2003 Mar, p31-36

Synthetic corundum

1,76

1,77

0

0

3,98

4,02

slihhtly purplish red , star ruby

chelsea : bright red

identical as natural

strong to very strong red with a moderate to strong chalky blue white overtone

very strong red

Gems & Gemology 1988 winter, p 237240

Synthetic corundum

1,76

1,768

0,008

0,008

3,99

4,04

reddish orange

weak pinkish red

strong orange-red

The Journal of Gemmology 1985 Vol 19, No 5 p389-403

Synthetic corundum

1,76

1,77

0,008

0,008

3,96

4

red

1,768

1,770

1,760

1,762

475, 476, 468, 659, 668, 692 , 694

weak to strong chalky red to orangy red

moderate to extremely strong chalky red to orangy red

Gems & Gemology 1983 Fall p130-148

Synthetic corundum

1,76

1,768

0,008

0,008

3,97

4,03

red, blue

blue : none; red: Cr spectrum

red: moderate red; blue : very weak chalky whitish blue

red: strong red, blue : inert

Gems & Gemology 1985 spring p35-39

Synthetic corundum

1,76

1,769

0,008

0,008

3,971

3,981

red

1,768

1,769

1,760

1,761

Gems & Gemology 1982 Fall, p166-168

Synthetic corundum

1,76

1,773

0,008

0,009

3,96

3,99

red

Douros, flux; 5 stones: 0.46-1.26ct

1,760

1,765

1,768

1,773

Cr³+

weak to moderate red

strong red

Zeitschrift der Deutschen Gemmologischen Gesellschaft 1994 Jun, p15-17

Synthetic corundum

1,76

1,768

0,008

0,008

3,99

3,99

red

Zeitschrift der Deutschen Gemmologischen Gesellschaft 1993 Sep, p66

Synthetic corundum

1,76

1,77

0,008

0,01

3,937

3,998

blue

hydrothermal, Tairus, 1.06-3.04ct

inert

moderate chalky green

The Gem and Jewelry Institute of Thailand - Lab Notes 2019 30/09

Synthetic corundum

1,76

1,77

0,008

0,01

3,96

3,98

flame fusion, diffusion treated, "spiders web" effect, Plato lines

strong chalky blue

inert

The Gem and Jewelry Institute of Thailand - Lab Notes 2019 26/10

Synthetic corundum

1,761

1,77

0,008

0,008

3,983

4,018

red

hydrothermal, Tairus, 0.48-0.65 ct

moderate red

strong red

The Gem and Jewelry Institute of Thailand - Lab Notes 2019 30/09

Synthetic corundum

1,761

1,769

0,008

0,008

3,99

3,99

red

medium red

strong red

Gems & Gemology 2022 Spring, p54

Synthetic corundum

1,762

1,77

0,008

0,008

3,98

4,01

orange

inert

weak chalky blue

The Journal of Gemmology 1985 Vol 19, No 5 p389-403

Synthetic corundum

1,762

1,77

0,008

0,008

3,97

4,03

orange, blue

orange: very weak to weak orange; blue: inert to strong: green to orange

orange: strong to very strong orange-red; blue: inert to very strong green to red

Gems & Gemology 1982 Fall, p140-153

Synthetic corundum

1,762

1,77

0,008

0,008

3,99

3,99

intense blue

hydrothermal

inert

inert

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2003 Mar, p31-36

Synthetic corundum

1,762

1,77

0,008

0,008

4

4

red

flux, made in Russia

Cr³+

weak red

strong red

Zeitschrift der Deutschen Gemmologischen Gesellschaft 1993 Dec, p137-138

Synthetic corundum

1,762

1,77

0,008

0,008

3,98

3,98

red

"Douros", flux

Cr³+

moderate red

strong red

Zeitschrift der Deutschen Gemmologischen Gesellschaft 1993 Dec, p138

Synthetic corundum

1,762

1,77

0,008

0,008

3,98

3,98

purplish red

Kashan, flux-grown, heat-treated

Cr-lines

moderate red

strong red

Gems & Gemology 2007 Summer, p175

Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

ne min

ne max

no min

no max

Reference

Synthetic corundum- sapphire - hydrothermal

1.745

1.77

0.008

0.012

4

4

1.745

1.760

1.760

1.770

http://www.geminterest.com 

Synthetic corundum- sapphire - Verneuil

1.745

1.77

0.008

0.012

3.99

4.01

1.745

1.760

1.760

1.770

http://www.geminterest.com 

Synthetic corundum - flux - Lechleitner

1.757

1.778

0.008

0.008

3.97

4.03

1.757

1.760

1.768

1.778

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

Synthetic corundum - Verneuil

1.757

1.78

0.008

0.008

3.97

4.03

1.757

1.768

1.765

1.780

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

Synthetic corundum - Chatham

1.757

1.78

0.008

0.008

3.95

4.06

1.757

1.768

1.765

1.780

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

Synthetic corundum- ruby - flux - Kashan, Knischka, Ramaura

1.757

1.775

0.008

0.008

3.97

4.03

1.757

1.768

1.765

1.775

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

Synthetic corundum

1.757

1.776

0.008

0.009

3.97

4.1

1.757

1.768

1.765

1.776

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

Synthetic corundum- ruby- Inamori

1.759

1.78

0.008

0.008

3.9

4.03

1.759

1.762

1.770

1.780

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

Synthetic corundum- ruby- Inamori

1.759

1.78

0.008

0.08

3.9

4.03

1.759

1.762

1.770

1.780

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

Synthetic corundum- ruby - Verneuil

1.759

1.773

0.007

0.009

3.99

4.01

1.759

1.770

1.767

1.773

http://www.geminterest.com 

Synthetic corundum- ruby - hydrothermal

1.759

1.77

0.008

0.009

4

4

1.759

1.765

1.767

1.770

http://www.geminterest.com 

Synthetic corundum- sapphire - flux

1.759

1.775

0.008

0.01

3.9

4

1.759

1.771

1.765

1.775

http://www.geminterest.com 

Synthetic corundum- ruby - flux

1.759

1.775

0.007

0.01

3.99

4.01

1.759

1.771

1.765

1.775

http://www.geminterest.com 

Synthetic corundum

1.759

1.775

0.008

0.01

3.97

4.03

Gemology Tools Professional 2010

Synthetic corundum

1.76

1.772

0.008

0.008

3.9

4.05

1.760

1.764

1.768

1.772

Gemmological Tables, Ulrich Henn, 2004 

Synthetic corundum

1.76

1.775

0.008

0.009

3.95

4.05

Gemmo.eu 

Synthetic corundum

1.76

1.775

0.008

0.009

3.95

4.05

Gemmo.eu 2013

Synthetic corundum- Seiko

1.762

1.778

0.008

0.01

3.9

4.03

1.762

1.764

1.767

1.778

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

Synthetic corundum

1.762

1.78

0.008

0.008

3.97

4.03

Bestimmungstabellen für Edelsteine, Birgit Günther, 2008 

Stone

Colour

Cause of colour

Reference

Synthetic corundum

blue star synthetic

dopant Fe2O3+TiO2

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

blue synthetic

dopant TiO2+ Fe2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

blue synthetic

dopant CoO

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

bluish green synthetic

dopant Ni²+,Ni³+

Gems & Gemology Spring 1999 p19

Synthetic corundum

bluish green synthetic

dopant Fe2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

bluish violet synthetic

Fe³+, Fe²+/Ti4+, Fe²+/Fe³+

The Journal of Gemmology, 2000, Vol27, N°1, p2

Synthetic corundum

brown synthetic

dopant CoO+Co2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

brown synthetic + irradiated

Mg + Ti dopant  (causing colour center)

The Journal ofGemmology, 2004,29,3,149-182

Synthetic corundum

brownish-violet synthetic

Mg dopant (causing colour center)

The Journal ofGemmology, 2004,29,3,149-182

Synthetic corundum

colour-change greyish-green to reddish-violet synt

V³+

The Journal of Gemmology, 2000, Vol27, N°1, p2

Synthetic corundum

dark red synthetic

dopant Cr2O3 + TiO2 + Fe2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

golden yellow synthetic

dopant NiO+MgO

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

green (emerald) synthetic

dopant Co2O3+MgO+ZnO+V2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

green (epidot) synthetic

dopant Fe2O3+NiO+TiO2

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

green (tourmaline) synthetic

dopant Co2O3+V2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

green colour change synthetic

dopant V2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

green synthetic

dopant Co2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

green synthetic

dopant Ni²+,Ni³+

Gems & Gemology Spring 1999 p19

Synthetic corundum

green synthetic

Mg dopant (causing colour center)

The Journal ofGemmology, 2004,29,3,149-182

Synthetic corundum

greyish purple synthetic

Mg dopant (causing colour center)

The Journal ofGemmology, 2004,29,3,149-182

Synthetic corundum

orange Padparadscha synthetic

dopant NiO+CrO3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

orange synthetic

Be + Cr dopant (causing colour center)

The Journal ofGemmology, 2004,29,3,149-182

Synthetic corundum

orange synthetic

Mg + Cr dopant (causing colour center)

The Journal ofGemmology, 2004,29,3,149-182

Synthetic corundum

orange synthetic

dopant NiO+Fe2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

orange synthetic

Mg dopant (causing colour center)

The Journal ofGemmology, 2004,29,3,149-182

Synthetic corundum

orange synthetic

Cr + Ni dopant (causing colour center)

The Journal ofGemmology, 2004,29,3,149-182

Synthetic corundum

pale brown synthetic

Be dopant (causing colour center)

The Journal ofGemmology, 2004,29,3,149-182

Synthetic corundum

pink synthetic

dopant Cr2O3 ~0.5%

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

pink synthetic

dopant CoO+Ti2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

pink synthetic

dopant Ti2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

pink synthetic Czochralski

Ti³ dopant

Gems & Gemology Fall 1995p188; Gems & Gemology 1992 Spring p 66

Synthetic corundum

red star synthetic

dopant Cr2O3+TiO2

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

red synthetic

dopant Cr2O3 ~5%

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

red synthetic

dopant MnF2

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

reddish-orange synthetic

Mn³+

The Journal of Gemmology, 2000, Vol27, N°1, p2

Synthetic corundum

violet synthetic

dopant TiO2+ Fe2O3+Cr2O3

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

yellow synthetic

Fe³+, minor Cr³+

The Journal of Gemmology, 2000, Vol27, N°1, p2

Synthetic corundum

yellow synthetic

dopant NiO

Zeitschrift der Deutschen Gemmologischen Gesellschaft,1988, 37, Nr3/4, p131

Synthetic corundum

yellow synthetic

Unreported mechanism involving despersed Ni ions (synthetic only)

Nassau (1980) (Ruby & Sapphire, Hughes 1997)

Synthetic corundum

yellow synthetic

Fe³+, minor Cr³+

The Journal of Gemmology, 2000, Vol27, N°1, p2

Synthetic corundum

yellow synthetic

dopant Ni³+

Gems & Gemology Spring 1999 p19

Synthetic corundum

yellow to brown synthetic

Mg + Fe dopant (causing colour center)

The Journal of Gemmology, 2004,29,3,149-182

Synthetic corundum

yellow to brown synthetic

Mg dopant (causing colour center)

The Journal of Gemmology, 2004,29,3,149-182

Stone

Colour

Reference

SiO2

Al2O3

MnO

MgO

FeO

TiO2

CaO

Na2O

Cr2O3

V2O3

Ga2O3

CoO

NiO

Synthetic corundum

colourless

Gems & Gemology 1999 Spring p38

0.004

0.006

0.018

0.003

Synthetic corundum

colourless

Gems & Gemology 1999 Spring p38

0.005

0

0.028

Synthetic corundum

colourless

Gems & Gemology 1999 Spring p38

0.003

0.009

0.019

Synthetic corundum

colourless

Gems & Gemology 1999 Spring p38

0.003

0.006

Synthetic corundum

colourless

Gems & Gemology 1999 Spring p38

0.003

0.014

Synthetic corundum

colourless

Gems & Gemology 1999 Spring p38

0.002

0.015

Synthetic corundum

colourless

Gems & Gemology 1999 Spring p38

0.007

0.038

Synthetic corundum

colourless

Gems & Gemology 1999 Spring p38

0.024

Synthetic corundum

colourless (Czochralski)

Gems & Gemology 1999 Spring p38

0.022

Synthetic corundum

colourless (Czochralski)

Gems & Gemology 1999 Spring p38

0.002

0.024

0.004

Synthetic corundum

colourless (Czochralski)

Gems & Gemology 1999 Spring p38

0.004

0.009

0.027

0.003

Synthetic corundum

colourless (Czochralski)

Gems & Gemology 1999 Spring p38

0.003

0.017

Synthetic corundum

colourless (Verneuil)

Gems & Gemology 1999 Spring p38

0.002

0.003

Synthetic corundum

colourless (Verneuil)

Gems & Gemology 1999 Spring p38

0.002

0.005

Synthetic corundum

colourless (Verneuil)

Gems & Gemology 1999 Spring p38

0.002

0.009

0.016

Synthetic corundum

colourless (Verneuil)

Gems & Gemology 1999 Spring p38

0.005

Synthetic corundum

red (Chatham flux)

Gems & Gemology 1998 Summer p88-91

98.98

0.006

0.01

0.009

0.04

0.956

0.001

0.002

Synthetic corundum

red (Czochralski Inamori)

Gems & Gemology 1998 Summer p88-91

99.37

0.007

0.005

0.022

0.595

Synthetic corundum

red (Czochralski Union Carbide)

Gems & Gemology 1998 Summer p88-91

98.96

0.007

0.003

0.002

1.08

0.001

Synthetic corundum

red (Douros flux)

Gems & Gemology 1998 Summer p88-91

99.32

0.004

0.085

0.013

0.01

0.484

0.064

Synthetic corundum

red (floating zone)

Gems & Gemology 1998 Summer p88-91

99.4

0.003

0.006

0.005

0.024

0.521

0.012

Synthetic corundum

red (Induced Finger prints flame fusion)

Gems & Gemology 1998 Summer p88-91

98.84

0.007

0.005

0.009

0.018

1.12

Synthetic corundum

red (Kashan flux)

Gems & Gemology 1998 Summer p88-91

99.57

0.003

0.007

0.096

0.023

0.291

0.005

0.001

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

94.79

0.01

0.01

0.03

0.01

0.22

0.03

0.01

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.03

95.46

0.02

0.01

1.1

0.06

0.01

0.01

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.01

94.92

0.04

0.05

0.02

0.26

0.02

0.01

0.02

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.02

96.64

0.01

0.01

0.07

0.01

0.1

0.01

0.01

0.03

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.03

96.63

0.03

0.01

0.3

0.04

0.01

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.01

96.73

0.01

0.03

0.01

0.1

0.08

0.02

0.03

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

96.93

0.03

0.01

0.03

0.01

0.06

0.01

0.01

0.02

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.02

95.86

0.01

0.01

0.01

0.01

0.13

0.02

0.02

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.01

95.64

0.02

0.01

0.03

1.5

0.06

0.02

0.05

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.01

96.82

0.01

0.01

0.01

0.12

0.03

0.01

0.01

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.01

95.59

0.02

0.01

0.01

0.01

0.55

0.05

0.01

0.04

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.01

95.56

0.01

0.02

0.01

0.43

0.05

0.02

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.01

95.19

0.07

0.03

0.58

0.05

0.01

0.02

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.02

95.33

0.02

0.03

0.7

0.03

0.01

0.02

Synthetic corundum

red (Kashan)

The Journal of Gemmology 1985, Vol 19 No 6 p477

0.03

96.24

0.01

0.01

0.06

0.32

0.02

Synthetic corundum

red (Knishka flux)

Gems & Gemology 1998 Summer p88-91

98.97

0.006

0.159

0.023

0.034

0.69

0.002

0.008

Synthetic corundum

red (Lechleitner flux)

Gems & Gemology 1998 Summer p88-91

99

0.006

0.026

0.031

0.933

0.008

Synthetic corundum

red (Ramaura flux)

Gems & Gemology 1998 Summer p88-91

99.01

0.005

0.112

0.039

0.822

0.008

Synthetic corundum

red (Ramaura flux)

Gems & Gemology 1998 Summer p88-91

99.23

0.006

0.037

0.033

0.688

0.005

Synthetic corundum

red (Tairus hydrothermal)

Gems & Gemology 1998 Summer p88-91

98.51

0.008

0.302

0.023

0.03

1.12

0.001

Synthetic corundum

red (Verneuil)

Gems & Gemology 1998 Summer p88-91

99.15

0.005

0.007

0.013

0.034

0.788

0.003

0.002