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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

Prehnite

1.61

1.632

0.022

0.022

2.9

2.9

yellow

 

11.14ct, transparent

 

 

 

 

 

 

none

brownish yellow

brownish yellow

ACAM Lab 

Prehnite

1.612

1.642

0.03

0.03

2.99

2.99

yellow

 

0.5ct, transparent

1.612

1.612

1.622

1.622

1.642

1.642

 

inert

inert

ACAM Lab  880

Prehnite

1.617

1.639

0.022

0.022

2.91

2.96

greenish yellow

Merelani, Tanzania

 

 

 

 

 

 

 

 

weak yellow

inert

Gems & Gemology 2007 Spring p60

Prehnite

1.617

1.645

0.026

0.026

2.92

2.93

light to medium greyish green and yellow

Mali

 

1.617

1.619

 

 

1.643

1.645

 

inert

inert

Gems & Gemology 2006 summer, p178-179

Prehnite

1.618

1.641

0.023

0.023

2.91

2.91

greenish yellow to yellow

Wave Hill, Northern Territories, Australia

semitransparent to translucent

 

 

 

 

 

 

none

weak orange

weak dull yellow

Gems & Gemology 2001 spring, p71

Prehnite

1.618

1.638

0.02

0.02

2.91

2.91

greenish yellow

Australia

10.55ct, translucent

 

 

 

 

 

 

 

inert

inert

GIA Gem Database  35485

Prehnite

1.618

1.65

 

 

2.9

2.9

greenish yellow

Australia

15ct, translucent

 

 

 

 

 

 

none

inert

inert

ACAM Lab  1876

Prehnite

1.62

1.62

 

 

2.87

2.92

greyish yellowish green

 

chatoyant cabochons, 4.95 - 5.40 ct, spot RI

 

 

 

 

 

 

 

 

 

Gems & Gemology 2007 Spring, p72

Prehnite

1.63

1.652

0.022

0.022

2.96

2.96

greyish green

 

13.61ct, translucent

 

 

 

 

 

 

 

inert

inert

GIA Gem Database  35468

 

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

Prehnite

1.61

1.64

 

 

2.8

2.95

 

 

 

 

 

 

John Sinkakas, Gemstone and mineral data book,1972 

Prehnite

1.61

1.673

0.02

0.036

2.8

2.95

1.610

1.637

1.615

1.647

1.632

1.673

Gemmological Tables, Ulrich Henn, 2004 

Prehnite

1.61

1.646

0.03

0.031

2.8

2.95

1.610

1.615

 

 

1.640

1.646

Tabellen zur Edelstein-Bestimmung, Pschichholz FGA, 1975 

Prehnite

1.61

1.673

0.02

0.033

2.8

3

1.610

1.637

1.615

1.650

1.632

1.673

http://www.geminterest.com 

Prehnite

1.61

1.64

0.03

0.03

2.8

2.95

 

 

 

 

 

 

Gems, R Webster, 5th edition 1994 

Prehnite

1.61

1.666

0.02

0.034

2.8

2.96

 

 

 

 

 

 

Gemmo.eu 

Prehnite

1.611

1.669

0.03

0.039

2.82

2.94

 

 

 

 

 

 

Bestimmungstabellen für Edelsteine, Birgit Günther, 1981 

Prehnite

1.611

1.669

0.021

0.039

2.8

3

1.611

1.632

 

 

1.632

1.669

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

Prehnite

1.611

1.665

0.021

0.033

2.8

3

 

 

 

 

 

 

http://www.gemmology.be 

Prehnite

1.611

1.665

0.021

0.033

2.8

3

1.611

1.632

1.615

1.642

1.632

1.665

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Prehnite

1.611

1.665

0.021

0.033

2.8

3

1.611

1.632

1.615

1.642

1.632

1.665

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

Prehnite

1.614

1.665

0.02

0.031

2.85

3

 

 

 

 

 

 

Gemology Tools Professional 2010

 

CAUSE OF COLOUR

 

MINERAL INCLUSIONS

 

LOCALITIES

Prehnite

 

Wave Hill

Northern Territory

Australia

Gems & Gemology 2001 spring, p71

Prehnite

 

 

 

Mali

Gems & Gemology 2006 summer, p178-179

Prehnite

Mawaya pit, Merelani Hills (Mererani), Umba Valley

Lelatema Mts

Arusha Region

Tanzania

Gems & Gemology 2007 Spring p60

 

CHEMICAL DATA (%)