|
INVESTIGATIONS
|
Stone |
RI min |
RI max |
Dens min |
Dens max |
Colour |
Location |
Info |
Spectrum |
UVS |
UVL |
Reference |
|
Gahnite |
1,791 |
1,791 |
4,18 |
4,294 |
blue |
Nigeria |
|
|
inert |
inert |
Gems & Gemology 2019
Fall, p 434 |
|
Gahnite |
1,791 |
1,798 |
4,34 |
4,66 |
blue |
Nigeria |
|
|
|
|
The Journal of Gemmology
2022 38(2), p183-193 |
|
Gahnite |
1,793 |
1,794 |
4,4 |
4,589 |
blue |
Jemaa, Nigeria |
|
|
|
|
The Journal of Gemmology
1982 Vol18, N°4 p265-276 |
|
Gahnite |
1,794 |
1,794 |
4,54 |
4,54 |
intense green |
Brazil |
|
|
|
|
Gemmologie, Zeitschrift
der Deutschen Gemmologischen Gesellschaft 1996 Mar, p1 |
|
Gahnite |
1,795 |
1,795 |
4,4 |
4,65 |
blue |
Nigeria |
0.17 and 0.19ct |
|
|
|
The Journal of Gemmology
2018 36(2), p 96-97 |
|
Gahnite |
1,798 |
1,798 |
4,64 |
4,64 |
green |
Sri Lanka |
transparent |
|
|
|
The Journal of Gemmology
1972 N°1, p8 |
|
Gahnite |
|
|
4,74 |
4,74 |
very dark green |
Barra de Salinas, Minas
Gerais, Brazil |
17.54ct |
broad absorption below
490 and above 560, line at 515nm |
inert |
inert |
GIA Gem Database 34280 |
TABLES
|
Stone |
RI min |
RI max |
Dens min |
Dens max |
Reference |
|
Gahnite |
1.776 |
1.806 |
4.35 |
4.63 |
Gemmo.eu 2017 |
|
Gahnite |
1.79 |
1.82 |
4.38 |
4.62 |
Tables of Gemstone
Identification, Roger Dedeyne, Ivo Quintens, 2007 |
|
Gahnite |
1.791 |
1.818 |
4 |
4.6 |
Bestimmungstabellen für Edelsteine, Birgit Günther,
2008 |
|
Gahnite |
1.792 |
1.82 |
4 |
4.64 |
Gemme, Dati per l'identificazione, P. De Stefano et
al, 1993 |
|
Gahnite |
1.792 |
1.803 |
4.4 |
4.6 |
Gemmological Tables, Ulrich Henn, 2004 |
|
Gahnite |
1.798 |
1.805 |
4.4 |
4.4 |
Tabellen zur Edelstein-Bestimmung, Pschichholz FGA,
1975 |
|
Gahnite |
1.798 |
1.8 |
4.4 |
4.64 |
Gems, R Webster, 5th edition
1994 |
|
Gahnite |
1.8 |
1.81 |
4 |
4.62 |
http://www.geminterest.com |
|
Gahnite synthetic |
1.805 |
1.805 |
4.4 |
4.4 |
Bestimmungstabellen für Edelsteine, Birgit Günther,
1981 |
|
Gahnite |
1.805 |
1.805 |
4 |
4.62 |
http://www.gemmology.be |
|
Gahnite |
1.805 |
1.805 |
4.4 |
4.59 |
Michael O'Donoghue, Gems:
Their Sources, Descriptions and Identification (2006), 873pp
|
|
Gahnite |
|
|
4.4 |
4.4 |
John Sinkakas, Gemstone and
mineral data book,1972 |
CAUSE OF
COLOUR
|
Stone |
Colour |
Cause
of colour |
Reference |
|
Gahnite |
blue |
Fe²+ in octahedral coordination |
Gems & Gemology Summer 1988 |
MINERAL
INCLUSIONS
|
Inclusion |
Stone |
Reference |
|
beryl |
Gahnite - spinel group |
The Journal of Gemmology
1982, Vol18, N°4,p265-276 |
|
columbite |
Gahnite - spinel group |
The Journal of Gemmology
1982, Vol18, N°4,p265-276 |
|
hematite |
Gahnite - spinel group |
The Journal of Gemmology
1982, Vol18, N°4,p265-276 |
|
mica |
Gahnite - spinel group |
The Journal of Gemmology
1982, Vol18, N°4,p265-276 |
|
quartz |
Gahnite - spinel group |
The Journal of Gemmology
2022 , 38(2), p185 |
|
sphalerite |
Gahnite - spinel group |
Gems & Gemology Fall
2019 p 435 |
|
zircon |
Gahnite - spinel group |
The Journal of Gemmology
1982, Vol18, N°4,p265-276 |
LOCALITIES
|
STONE |
LOCALITIES |
REFERENCE |
|||
|
Gahnite |
Jemaa |
Kaduna |
|
Nigeria |
The Journal of Gemmology
1982, Vol18, N°3, p266 |
CHEMICAL DATA (%)