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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

Manganotantalite

2.16

2.16

 

 

7.73

7.97

scarlet red

Morrua, Mozambique

0.58ct, strong dispersion, somewhat metallic luster

 

 

 

 

 

 

broad band in yellow-green and in the violet

inert

inert

The Journal of Gemmology 1979 Vol 16, N6, p363-364

Manganotantalite

 

 

 

 

7.76

7.81

dark red

Grangal, Nuristan, Afghanistan

1.10ct and 4.66ct, strong doubling of facets

 

 

 

 

 

 

 

inert

inert

The Journal of Gemmology 2016 Vol 35, No. 2, p111-114

Manganotantalite

 

 

 

 

7.8

7.8

red-orange

Pakistan

9.90ct

 

 

 

 

 

 

broad absorption below 500nm  and between 540-580

inert

inert

GIA Gem Database  35449

Manganotantalite

 

 

 

 

8

8

red

Murrua, Zambezia Province, Mozambique

5.51ct

 

 

 

 

 

 

broad absorption below 490nm  and between 540-585

inert

inert

GIA Gem Database  35448

 

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

Manganotantalite

2.13

2.25

0.14

0.16

7.5

8

 

 

 

 

 

 

Gemmo.eu 2016

Manganotantalite

2.14

2.34

0.08

0.15

7.73

7.97

2.140

2.190

2.150

2.250

2.220

2.340

http://www.geminterest.com 

Manganotantalite

2.14

2.34

0.008

0.015

7.73

7.97

 

 

 

 

 

 

Gems, R Webster, 5th edition 1994 

Manganotantalite

2.14

2.34

0.08

0.15

7.73

8.1

2.140

2.190

 

 

2.220

2.340

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

Manganotantalite

2.19

2.34

0.015

0.015

7.73

7.97

2.190

2.190

2.250

2.250

2.340

2.340

Gemmological Tables, Ulrich Henn, 2004 

Manganotantalite

2.19

2.34

0.015

0.015

7.73

7.97

 

 

 

 

 

 

http://www.gemmology.be 

Manganotantalite

2.19

2.34

0.015

0.015

7.73

7.97

2.190

2.190

2.250

2.250

2.340

2.340

Joel Arem, Color Encyclopedia of Gemstones, 1987 

Manganotantalite

2.19

2.34

0.15

0.15

7.73

7.97

 

 

 

 

 

 

Gemology Tools Professional 2016

 

CAUSE OF COLOUR

 

MINERAL INCLUSIONS

 

LOCALITIES

STONE

LOCALITIES

REFERENCE

manganotantalite

Murrua (Morrua)

Alto Ligonha district

Zambezia Province

Mozambique

The Journal of Gemmology 1979, Vol16, N6, p363-364







 

CHEMICAL DATA (%)

Stone

Colour

Locality

Reference

MgO

FeO

Ta2O5

Nb2O5

Manganotantalite

dark red

Grangal

Afghanistan

The Journal of Gemmology 2016, Vol 35,No2, p113

12.5

0.32

74.5

12.7

Manganotantalite

dark red

Grangal

Afghanistan

The Journal of Gemmology 2016, Vol 35,No2, p113

12.5

1.12

71.6

14.8