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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

Montebrasite

1.61

1.635

0.025

0.025

2.96

2.96

yellowish green, transparent

Brazil

0.49ct

 

 

 

 

 

 

 

 

 

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2008 Dec, p117-118

Montebrasite

1.615

1.628

0.013

0.013

3.03

3.03

light yellowish green

Brazil

1.34ct, biaxial +

 

 

 

 

 

 

 

inert

inert

GIA Gem Database  35456

Montebrasite

1.615

1.644

0.029

0.029

3.03

3.03

light yellow, almost colourless

 

2.16 ct

1.615

1.615

1.623

1.623

1.644

1.644

 

 

weak violet

ACAM Lab  n871

Montebrasite

1.616

1.645

0.029

0.029

3.02

3.02

light greyish green

Brazil

biaxial +

 

 

 

 

 

 

 

 

 

Gemmologie, Zeitschrift der Deutschen Gemmologischen Gesellschaft 2010 59/3-4, p95-102

 

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

Montebrasite

1.593

1.647

0.02

0.03

2.96

3.11

 

 

 

 

 

 

Gemmo.eu 2015

Montebrasite

1.594

1.633

0.021

0.026

2.98

3.03

1.594

1.611

1.603

1.619

1.615

1.633

http://www.geminterest.com 

Montebrasite

1.594

1.646

0.02

0.05

2.98

3.05

1.594

1.615

1.608

1.624

1.616

1.646

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

Montebrasite

1.594

1.633

0.02

0.027

2.98

3.085

 

 

 

 

 

 

Gemology Tools Professional 2010

Montebrasite

1.611

1.633

0.022

0.022

3

3

 

 

 

 

 

 

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

Montebrasite

1.622

1.646

0.02

0.03

2.98

3.08

 

 

 

 

 

 

http://www.gemmology.be 

 

CAUSE OF COLOUR

 

MINERAL INCLUSIONS

 

LOCALITIES

STONE

LOCALITIES

REFERENCE

Montebrasite

 

Mogi das Cruzes

Sao Paulo

Brazil

Joel Arem, Color Encyclopedia of Gemstones, 1987

 

CHEMICAL DATA (%)

Stone

Colour

Locality

Reference

Al2O3

Fe2O3

P2O5

Montebrasite

 

 

Brazil

Zeitschrift der Deutschen Gemmologischen Gesellschaft, 2010, Nr 3/4, p99

48.4

0.02

35.15