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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

Labradorite

1.553

1.561

0.008

0.008

2.69

2.69

yellowish

 

 

 

 

 

 

 

 

 

 

 

ACAM labo 

Labradorite sunstone

1.553

1.563

0.007

0.011

2.68

2.7

red and green

Congo ?

1.97-4.856 ct

1.553

1.555

 

 

1.562

1.563

 

inert

weak to distinct orange

The Journal of Gemmology 2004 Vol 29, N°1, p15-23

Labradorite

1.554

1.562

0.008

0.008

2.69

2.69

colourless

 

 

 

 

 

 

 

 

 

 

 

ACAM labo 

Labradorite

1.555

1.563

0.008

0.008

2.7

2.7

 

Oregon, USA

50.5% anorthite (=almost andesine)

1.555

1.555

1.558

1.558

1.563

1.563

 

 

 

Zeitschrift der Deutschen Gemmologischen Gesellschaft 1992 Apr, p49-51

Labradorite

1.558

1.568

0.01

0.01

2.7

2.7

light yellow

 

 

 

 

 

 

 

 

 

 

 

Gems & Gemology 1963 Winter, p114

Labradorite

1.56

1.571

0.009

0.01

2.71

2.72

pale yellow, transparent

Casas Grandes, Chihuahua, Mexico

 

 

 

 

 

 

 

 

very weak orange

inert

Gems & Gemology 2006 winter, p 274

Labradorite sunstone

1.56

1.57

0.007

0.009

2.711

2.717

yellow, red-orange, bluish-green, yellowish green, orange, violet

Rabbit hilly, Lake County, Oregon

 

1.560

1.563

 

 

1.569

1.570

 

 

 

Gems & Gemology 1976 Summer p 162-167

Labradorite

1.56

1.572

0.012

0.012

2.72

2.72

 

 

0.6ct

 

 

 

 

 

 

 

 

 

ACAM labo 

Labradorite sunstone

1.56

1.572

0.007

0.01

2.7

2.72

pale red and green

Oregon, USA

2.91 and 3.63 ct, slight 'schiller' effect

1.560

1.565

 

 

1.570

1.572

 

inert

inert

The Journal of Gemmology 2004 Vol 29, N°1, p15-23

Labradorite

1.561

1.57

0.009

0.009

2.69

2.72

pale yellow

Ketchikan, Alaska, USA

transparent

 

 

 

 

 

 

none

weak red

inert

Gems & Gemology 2009 spring p 67

Labradorite

1.561

1.569

0.008

0.008

2.71

2.71

dark orangy red

Ponderosa Mine, Burns, Harney County, Oregon, USA

2.60ct

 

 

 

 

 

 

broad absorption below 430 and between 570-590nm

inert

inert

GIA Gem Database  33138

Labradorite sunstone

1.563

1.572

0.009

0.009

2.67

2.72

moderate to heavily saturated red, pink, orange, green: aventurescence

Ponderosa mine, Oregon

 

1.563

1.563

1.568

1.568

1.572

1.572

 

inert

inert

Gems & Gemology 1991 winter, p220-233

Labradorite

1.566

1.572

0.006

0.006

2.72

2.72

light orangy yellow

Plush, Lake County, Oregon, USA

22.01ct

 

 

 

 

 

 

 

inert

inert

GIA Gem Database  33097

 

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

Labradorite

1.53

1.572

0.012

0.012

2.69

2.72

1.530

1.560

1.563

1.563

1.572

1.572

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Labradorite

1.55

1.573

0.007

0.012

2.67

2.72

1.550

1.564

1.558

1.568

1.564

1.573

http://www.geminterest.com 

Labradorite

1.553

1.573

0.007

0.012

2.69

2.72

1.553

1.563

1.563

1.563

1.562

1.573

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

Labradorite

1.553

1.574

0.007

0.012

2.67

2.73

 

 

 

 

 

 

Gemmo.eu 2017

Labradorite

1.554

1.573

0.008

0.01

2.68

2.71

1.55

1.56

1.56

1.57

1.56

1.57

Michael O'Donoghue, Gems: Their Sources, Descriptions and Identification (2006),  873pp 

Labradorite

1.555

1.573

0.008

0.012

2.65

2.76

1.555

1.563

 

 

1.564

1.573

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

Labradorite

1.556

1.571

0.009

0.01

2.69

2.7

1.556

1.561

1.559

1.565

1.565

1.571

Gemmological Tables, Ulrich Henn, 2004 

Labradorite

1.559

1.571

0.009

0.011

2.65

2.75

 

 

 

 

 

 

Bestimmungstabellen für Edelsteine, Birgit Günther, 1981 

Labradorite

1.559

1.568

0.009

0.009

2.65

2.75

 

 

 

 

 

 

Tabellen zur Edelstein-Bestimmung, Pschichholz FGA, 1975 

Labradorite

1.56

1.573

0.008

0.01

2.7

2.72

 

 

 

 

 

 

John Sinkakas, Gemstone and mineral data book,1972 

Labradorite

1.56

1.572

0.012

0.012

2.69

2.72

 

 

 

 

 

 

http://www.gemmology.be 

Labradorite

1.56

1.573

0.008

0.008

2.68

2.69

 

 

 

 

 

 

Gems, R Webster, 5th edition 1994 

 

CAUSE OF COLOUR

Stone

Colour

Cause of colour

Reference

Labradorite

multicolours

diffraction of light by the internal lamellar structure

Gems & Gemology Summer 1988

Labradorite

green and orange-pink

could be Cu-InterValenceChargeTransfer or Cu° pairs

Gems & Gemology Summer 1988

 

MINERAL INCLUSIONS

Inclusion

Stone

Reference

hematite

Labradorite

Gemmological Tables, Ulrich Henn , GGA, 2004

ilmenite

Labradorite

Gemmological Tables, Ulrich Henn , GGA, 2004

magnetite

Labradorite

Gemmological Tables, Ulrich Henn , GGA, 2004

olivine

Labradorite

Gems & Gemology 2016 Spring p 77-78

pyrite

Labradorite

Gems & Gemology 1976 Summer p162-167

 

LOCALITIES

STONE

LOCALITIES

REFERENCE

Labradorite

 

Nain

Labrador

Canada

Gemmologie Dec 2001 p185

Labradorite

 

 

 

Finland

Gemmologie Dec 2001 p185

Labradorite

 

 

 

India

Gemmologie Dec 2001 p185

Labradorite

Ambatondrazaka District

Alaotra-Mangoro Region

Toamasina (Tamatave) Province

Madagascar

Gemmologie, Dez 1999, p196

Labradorite

Betioky Department

Southwestern Region

Tuléar (Toliara) Province

Madagascar

Gemmologie, Dez 1999,p196

Labradorite

 

 

 

Mexico

Gemmologie Dec 2001 p185

Labradorite

 

Casas Grandes area

Chihuahua

Mexico

Gems & Gemology 2006 winter, p 274

Labradorite

 

 

 

Russia

Gemmologie Dec 2001 p185

Labradorite

Ketchikan District

Prince of Wales-Outer Ketchikan Borough

Alaska

USA

Gems & Gemology Spring 2009, p67

Labradorite - sunstone

Rabbit Hills

Lake County

Oregon

USA

Gemmologie  Dec 2001 p185

Labradorite - sunstone

Dust Devil Mine, Plush

Lake County

Oregon

USA

Gems & Gemology 2013 Fall

Labradorite - sunstone

Ponderosa Sunstones Mine

Harney County

Oregon

USA

Gems & Gemology 2013 Fall

 

CHEMICAL DATA (%)

Stone

Colour

Locality

Reference

SiO2

Al2O3

MnO

FeO

TiO2

CaO

Na2O

K2O

P2O5

Labradorite

green (two directions), red (along 1 direction)

Ponderosa Mine, Oregon

USA

Gems & Gemology 1991 Winter p227

51.03

31.13

0.01

0.29

0.044

14.12

3.31

0.05

0.008

Labradorite

colourless

Ponderosa Mine, Oregon

USA

Gems & Gemology 1991 Winter p227

51.76

30.43

 

0.38

 

14.16

3.18

0.04

 

Labradorite

red

Ponderosa Mine, Oregon

USA

Gems & Gemology 1991 Winter p227

52.05

29.98

 

0.43

 

14.23

3.24

0.005

 

Labradorite

green

Ponderosa Mine, Oregon

USA

Gems & Gemology 1991 Winter p227

51.52

30.61

 

0.39

 

14.34

3.1

0.04

 

Labradorite

colourless

Ponderosa Mine, Oregon

USA

Gems & Gemology 1991 Winter p227

51.11

31.01

0.001

0.31

0.047

14.09

3.36

0.05

0.007

Labradorite

red

Ponderosa Mine, Oregon

USA

Gems & Gemology 1991 Winter p227

51.83

30.51

0.01

0.32

0.043

1343

3.74

0.11

0.009

Labradorite

green (one direction), red (along 2 directions)

Ponderosa Mine, Oregon

USA

Gems & Gemology 1991 Winter p227

50.93

31.2

0.011

0.29

0.045

14.23

3.24

0.05

0.008