|
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 |
Nuummite |
1.635 |
1.663 |
0.02 |
0.022 |
3.18 |
3.37 |
matrix: light grey to almost black; iridescence: green, metallic blue,
yellow to golden, rarely violet; mostly only two colours of the same end of
the spectrum |
50 km of Nuuk, Greenland |
cause of iridiscence : very thin lamellae of gedrite (0.8µm) and
anthophyllite (0.2µm) |
|
|
|
|
|
|
general absorption from 485, broad lines at 505 and 545nm |
dark violet |
dark violet |
Gems & Gemology 1987 spring, p36-42 |
Nuummite |
1.649 |
1.669 |
|
|
2.93 |
3.03 |
black, dark brown, with blue and bluish green or golden iridescence |
Sahara Desert, Mauretania |
cabochons of 8-20ct |
|
|
|
|
|
|
|
inert |
inert |
Gems & Gemology 2011 Fall, p242-243 |
Nuummite |
1.65 |
1.65 |
|
|
3.2 |
3.2 |
|
|
|
|
|
|
|
|
|
|
|
|
The Australian Gemmologist 1985 November, p 461 |
Nuummite |
1.65 |
1.66 |
|
|
3.08 |
3.1 |
violet-blue |
Simiuttat, Greenland |
|
|
|
|
|
|
|
no features |
inert |
inert |
The Journal of Gemmology 2016 Vol 35 (4), p330-338 |
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 |
Nuummite |
1.635 |
1.663 |
0.022 |
0.022 |
3.18 |
3.37 |
1.635 |
1.641 |
|
|
1.657 |
1.663 |
Gemmological Tables, Ulrich Henn,
2004 |
Nuummite |
1.635 |
1.663 |
0.022 |
0.022 |
3.18 |
3.37 |
1.635 |
1.641 |
|
|
1.657 |
1.663 |
Tables of Gemstone Identification, Roger Dedeyne, Ivo Quintens, 2007 |
Nuummite |
1.64 |
1.66 |
0.02 |
0.02 |
3.24 |
3.24 |
|
|
|
|
|
|
Gems, R Webster, 5th edition 1994 |
CAUSE OF
COLOUR
Stone |
Colour |
Cause
of colour |
Reference |
Nuummite |
multicolour |
iridescence, likely diffraction |
Gems & Gemology Summer 1988 |
MINERAL
INCLUSIONS
LOCALITIES
STONE |
LOCALITIES |
REFERENCE |
|||
nuummite |
|
|
|
Greenland |
Gems & Gemology 2011 Fall, p242-243 |
nuummite |
|
Sahara Desert |
|
Mauretania |
Gems & Gemology 2011 Fall, p242-243 |
CHEMICAL DATA
(%)