Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

Colour

Location

Info

ne min

ne max

no min

no max

Spectrum

UVS

UVL

Reference

Willemite

1.685

1.715

0.03

0.03

4.25

4.25

light orangy yellow

Franklin District, New Jersey, USA

2.42ct

lines at 428, 440, 450nm, band below 415nm

weak green

weak green

GIA Gem Database  35547

Willemite

1.69

1.722

0.032

0.032

4.25

4.25

orange

Franklin District, New Jersey, USA

8.71ct

lines at 490, 544nm, band below 440nm

weak green

inert

GIA Gem Database  35244

Willemite

1.69

1.718

0.028

0.028

4.23

4.23

yellowish orange

Tsumeb, Namibia

4.41ct

no features

weak yellowish green

weak orangy yellow

GIA Gem Database  34742

Willemite

1.695

1.723

0.028

0.028

very light yellow to slightly brown

Franklin mining district, New Jersey, USA

0.42ct

strong yellowish-green

inert

www.spec4gem.info 2019 13 january

Willemite

1.696

1.724

0.028

0.028

4.29

4.29

orange

Franklin District, Sussex County, New Jersey, USA

10.15ct

broad absorption below 425; lines at 490, 550nm

weak green

inert

GIA Gem Database  34123

Willemite

1.699

1.721

0.022

0.022

4.24

4.24

orangy yellow

Franklin District, Sussex County, New Jersey, USA

9.54ct

broad absorption below 415; lines at 428, 440, 452, 480, 500nm

medium green

medium green

GIA Gem Database  35546

Stone

RI min

RI max

Biref min

Biref max

Dens min

Dens max

ne min

ne max

no min

no max

Reference

Willemite

1.687

1.723

0.028

0.029

3.89

4.18

1.716

1.723

1.687

1.695

Gemmological Tables, Ulrich Henn, 2004 

Willemite

1.688

1.726

0.021

0.031

3.88

4.27

Gemmo.eu 2019

Willemite

1.69

1.723

0.028

0.033

3.89

4.2

1.719

1.723

1.690

1.691

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

Willemite

1.69

1.72

0.03

0.03

3.89

4.18

Tabellen zur Edelstein-Bestimmung, Pschichholz FGA, 1975 

Willemite

1.69

1.72

0.028

0.028

3.89

4.18

Gems, R Webster, 5th edition 1994 

Willemite

1.69

1.723

0.028

0.033

3.89

4.18

1.719

1.723

1.690

1.691

Bestimmungstabellen für Edelsteine, Birgit Günther, 2008 

Willemite

1.69

1.715

0.01

0.033

3.89

4.18

1.715

1.730

1.690

1.720

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

Willemite

1.691

1.719

0.028

0.028

3.89

4.1

1.719

1.719

1.691

1.691

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Willemite

1.691

1.719

0.028

0.028

3.89

4.1

http://www.gemmology.be 

Willemite

1.691

1.72

0.018

0.028

3.9

4.18

John Sinkakas, Gemstone and mineral data book,1972 

Willemite

1.691

1.719

0.028

0.028

3.89

4.18

1.719

1.719

1.691

1.691

http://www.geminterest.com 

Willemite

1.691

1.719

0.028

0.028

4

4.2

Gemology Tools Professional 2010

Willemite

1.691

1.724

0.028

0.028

3.89

4.1

1.719

1.724

1.691

1.695

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

Stone

Colour

Cause of colour

Reference

Willemite

yellow, yellow-green

Mn²+ in tetrahedral coordination

Gems & Gemology Summer 1988

STONE

LOCALITIES

REFERENCE

Willemite

Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry)

Mont Saint-Hilaire, Rouville County

Quebec

Canada

Zeitschrift der Deutschen Gemmologischen Gesellschaft, 1994, Dez, p137