|
INVESTIGATIONS
Stone |
RI min |
RI max |
Biref min |
Biref max |
Dens min |
Dens max |
Colour |
Location |
Info |
ne min |
ne max |
no min |
no max |
Spectrum |
UVS |
UVL |
Reference |
Taaffeite |
1.715 |
1.729 |
0.004 |
0.006 |
3.6 |
3.69 |
light purple, purplish violet, violet, greyish violet, bluish violet,
bluish grey |
Tanzania, Africa |
|
1.715 |
1.723 |
1.719 |
1.729 |
|
inert |
inert |
The Journal of Gemmology 2007 Nr 7/8, p367-382 |
Taaffeite |
1.715 |
1.722 |
0.007 |
0.007 |
3.62 |
3.62 |
purple |
Sri Lanka |
5.32ct |
|
|
|
|
no features |
inert |
inert |
GIA Gem Database 34933 |
Taaffeite |
1.715 |
1.72 |
0.005 |
0.005 |
3.62 |
3.62 |
light brownish red |
Ratnapura, Sri Lanka |
11.23ct |
|
|
|
|
no features |
inert |
weak green |
GIA Gem Database 34931 |
Taaffeite |
1.716 |
1.728 |
0.004 |
0.006 |
3.61 |
3.67 |
purple to purplish red |
Sri Lanka and Birma |
Cr-bearing taaffeites, small shift of colour between day and incandescent
light |
1.716 |
1.720 |
1.722 |
1.728 |
Cr and Fe |
|
|
Gems & Gemology 2000 spring, p50-59 |
Taaffeite |
1.716 |
1.719 |
0.003 |
0.003 |
3.64 |
3.64 |
pinkish |
Sri Lanka |
0.34ct |
|
|
|
|
|
inert |
inert |
ACAM lab
2280 |
Taaffeite |
1.716 |
1.721 |
0.004 |
0.004 |
3.6 |
3.61 |
pale purplish pink |
Mogok, Myanmar |
1.33ct - 5.16ct |
1.72 |
1.72 |
1.72 |
1.72 |
|
inert |
inert to weak chalky green or white |
The Gem and Jewelry Institute of Thailand - Lab Notes 2014 22 oct |
Taaffeite |
1.717 |
1.727 |
0.004 |
0.005 |
3.62 |
3.66 |
greyish violet, purplish red |
Sri Lanka |
|
1.717 |
1.722 |
1.721 |
1.727 |
|
|
|
The Australian Gemmologist 2006 jul-sep, p486 |
Taaffeite |
1.717 |
1.723 |
0.004 |
0.006 |
3.6 |
3.62 |
|
Elahera, Sri Lanka |
|
|
|
|
|
|
inert |
inert |
Gems & Gemology 1986 Summer, p91 |
Taaffeite |
1.717 |
1.123 |
0.004 |
0.005 |
3.6 |
3.61 |
mauve |
|
2 stones, dispersion (B-G): 0.019 |
1.717 |
1.718 |
1.721 |
1.723 |
|
|
|
Gems & Gemology 1968 Spring, p259 |
Taaffeite |
1.718 |
1.722 |
0.004 |
0.004 |
3.6 |
3.6 |
red |
|
0.58ct |
|
|
|
|
emission line around 684nm |
|
|
Zeitschrift der Deutschen Gemmologischen
Gesellschaft 1991 Apr, p33-37 |
Taaffeite |
1.718 |
1.724 |
0.006 |
0.006 |
3.67 |
3.67 |
bluish, smoky grey in daylight |
|
0.70 ct |
|
|
|
|
|
|
|
The Journal of Gemmology 1986 Vol20, N°3, p151 |
Taaffeite |
1.718 |
1.722 |
0.004 |
0.004 |
3.59 |
3.59 |
sapphir blue |
|
3.34 ct |
|
|
|
|
|
|
|
Gems & Gemology 1980 Spring, p268 |
Taaffeite |
1.72 |
1.724 |
0.004 |
0.004 |
3.61 |
3.61 |
colour canging from bluish to reddish |
Sri Lanka |
12.23ct |
|
|
|
|
|
|
|
Zeitschrift der Deutschen Gemmologischen
Gesellschaft 1989 Aug, p89-94 |
Taaffeite |
1.72 |
1.724 |
0.004 |
0.004 |
3.63 |
3.63 |
violetish blue |
Sri Lanka |
3.23ct |
|
|
|
|
lines at 465, 480nm |
inert |
inert |
GIA Gem Database 34196 |
Taaffeite |
1.72 |
1.726 |
0.006 |
0.006 |
3.63 |
3.63 |
purplish red |
Sri Lanka |
11.23ct |
|
|
|
|
lines at 466, 482nm |
inert |
inert |
GIA Gem Database 34183 |
Taaffeite |
1.72 |
1.72 |
|
|
3.68 |
3.68 |
purplish brown |
|
1.44ct, cabochon, cat's-eye, spot RI, reflective planar inclusions with
striations |
|
|
|
|
|
inert |
inert |
Gems & Gemology 1999 spring p 46 |
Taaffeite |
1.721 |
1.727 |
0.006 |
0.006 |
3.63 |
3.63 |
bluish to reddish colour-changing |
Sri Lanka |
2.82ct |
|
|
|
|
intensive 555nm and 463nm, additional 624, 470, 415, 402nm |
|
|
Gemmologie, Zeitschrift der Deutschen
Gemmologischen Gesellschaft 2000 Mar, p1 |
Taaffeite |
1.721 |
1.726 |
0.005 |
0.005 |
3.62 |
3.62 |
purplish red |
Sri Lanka |
1.23ct |
|
|
|
|
broad absorption below 425nm |
inert |
weak red |
GIA Gem Database 34186 |
Taaffeite |
1.721 |
1.726 |
0.005 |
0.005 |
3.61 |
3.61 |
purplish red |
Sri Lanka |
2.26ct |
|
|
|
|
line at 466nm |
inert |
inert |
GIA Gem Database 34188 |
Zn-Taaffeite |
1.724 |
1.735 |
0.004 |
0.006 |
3.69 |
3.78 |
|
Ratnapura, Sri Lanka |
|
1.724 |
1.730 |
1.729 |
1.735 |
|
|
|
The Journal of Gemmology 2005 29, 5/6, p290-298 |
Zn-Taaffeite |
1.726 |
1.73 |
0.004 |
0.004 |
3.71 |
3.71 |
reddish violet |
Sri Lanka |
|
1.726 |
1.726 |
1.730 |
1.730 |
|
|
|
Zeitschrift der Deutschen Gemmologischen
Gesellschaft 1985 34, Nr 1/2, p20-23 |
Zn-Taaffeite |
1.726 |
1.73 |
0.004 |
0.004 |
3.71 |
3.71 |
reddish violet |
Sri Lanka |
1.25ct |
|
|
|
|
|
|
|
The Journal of Gemmology 1985 Vol 19, No 6, p494-497 |
Taaffeite |
1.73 |
|
|
|
3.6 |
3.6 |
purplish red |
Myanmar |
6.23ct |
|
|
|
|
|
inert |
inert |
GIA Gem Database 34665 |
Taaffeite |
|
|
|
|
|
|
brownish grey |
|
0.61ct |
|
|
|
|
|
inert |
inert |
Gems & Gemology 1987 Fall, p168 |
TABLES
Stone |
RI
min |
RI
max |
Biref
min |
Biref
max |
Dens
min |
Dens
max |
ne
min |
ne
max |
no
min |
no
max |
Reference |
Taaffeite |
1.715 |
1.747 |
0.004 |
0.009 |
3.6 |
3.7 |
1.715 |
1.741 |
1.721 |
1.747 |
Gemme, Dati per l'identificazione, P. De
Stefano et al, 1993 |
Taaffeite |
1.716 |
1.73 |
0.004 |
0.004 |
3.59 |
3.72 |
1.716 |
1.726 |
1.720 |
1.730 |
Gemmological Tables, Ulrich Henn,
2004 |
Taaffeite |
1.716 |
1.725 |
0.003 |
0.007 |
3.58 |
3.64 |
|
|
|
|
Gemmo.eu
|
Taaffeite |
1.717 |
1.73 |
0.004 |
0.009 |
3.6 |
3.71 |
|
|
|
|
http://www.gemmology.be |
Taaffeite |
1.717 |
1.723 |
0.003 |
0.004 |
36 |
3.61 |
1.717 |
1.722 |
1.718 |
1.723 |
Tabellen zur Edelstein-Bestimmung,
Pschichholz FGA, 1975 |
Taaffeite |
1.717 |
1.735 |
0.004 |
0.009 |
3.6 |
3.71 |
1.717 |
1.726 |
1.721 |
1.735 |
Joel Arem, Color Encyclopedia of Gemstones,
1987 |
Taaffeite |
1.717 |
1.747 |
0.003 |
0.009 |
3.59 |
3.71 |
1.717 |
1.741 |
1.721 |
1.747 |
http://www.geminterest.com |
Taaffeite |
1.717 |
1.724 |
0.004 |
0.009 |
3.6 |
3.62 |
1.717 |
1.720 |
1.721 |
1.724 |
Tables of Gemstone Identification, Roger Dedeyne,
Ivo Quintens, 2007 |
Taaffeite |
1.718 |
1.722 |
0.004 |
0.004 |
3.6 |
3.61 |
|
|
|
|
John Sinkakas, Gemstone and mineral data
book,1972 |
Taaffeite |
1.718 |
1.722 |
0.004 |
0.004 |
3.6 |
3.61 |
|
|
|
|
Gems, R Webster, 5th edition 1994 |
Taaffeite |
1.719 |
1.747 |
0.004 |
0.009 |
3.59 |
3.67 |
|
|
|
|
Bestimmungstabellen für Edelsteine,
Birgit Günther, 2008 |
Taaffeite |
1.719 |
1.725 |
0.004 |
0.005 |
3.6 |
3.62 |
|
|
|
|
Gemology Tools Professional 2010 |
Zn-Taaffeite |
1.724 |
1.735 |
0.004 |
0.006 |
3.69 |
3.78 |
|
|
|
|
Tables of Gemstone Identification, Roger Dedeyne,
Ivo Quintens, 2007 |
CAUSE OF
COLOUR
Stone |
Colour |
Cause
of colour |
Reference |
Taaffeite |
red to violet |
Cr³+ in octahedral coordination |
Gems & Gemology Summer 1988 |
MINERAL
INCLUSIONS
Inclusion |
Stone |
Reference |
apatite |
Taaffeite |
E.J. Gübelin and J.I. Koivula, Photoatlas of inclusions in Gemstones,
volume 2 (2005) |
hematite |
Taaffeite |
Gems & Gemology 2000 spring p54 |
limonite |
Taaffeite |
Gems & Gemology 2000 spring p54 |
magnesite |
Taaffeite |
Gems & Gemology 2000 spring p54 |
monazite |
Taaffeite |
Gems & Gemology 2000 spring p54 |
muscovite |
Taaffeite |
Gems & Gemology 1984 Fall p161 |
phlogopite |
Taaffeite |
Gems & Gemology 1986 Summer p91 |
spinel |
Taaffeite |
Gems & Gemology 1986 Summer p91 |
uraninite |
Taaffeite |
Gems & Gemology 2000 spring p54 |
xenotime |
Taaffeite |
Gems & Gemology 2000 spring p54 |
zircon |
Taaffeite |
Gems & Gemology 2000 spring p54 |
LOCALITIES
STONE |
LOCALITIES |
REFERENCE |
|||
Taaffeite |
|
Elehara |
|
Sri Lanka |
Gems & Gemology 1986 Summer, p91 |
CHEMICAL DATA
(%)
Stone |
Colour |
Locality |
Reference |
Al2O3 |
MnO |
MgO |
FeO |
TiO2 |
Cr2O3 |
V2O3 |
Ga2O3 |
ZnO |
BeO |
|
Taaffeite |
greyish violet |
|
Myanmar |
Gems & Gemology 2000 Spring p52 |
72.14 |
0.02 |
21.58 |
0.8 |
0.01 |
0.01 |
0.01 |
0.05 |
0.09 |
4.45 |
Taaffeite |
dark purplish violet |
Delwela |
Sri Lanka |
The Journal of Gemmology 2005, 29, 5/6,
290-298 |
70.58 |
0.05 |
17.74 |
5.62 |
0.03 |
0.02 |
|
|
0.82 |
4.35 |
Taaffeite |
greyish violet |
Mudunkotuwa |
Sri Lanka |
The Journal of Gemmology 2005, 29, 5/6,
290-298 |
70.13 |
0.06 |
15.63 |
1.76 |
0.01 |
0.01 |
0.02 |
|
8.87 |
4.31 |
Taaffeite |
light violet |
|
Sri Lanka |
The Journal of Gemmology 2005, 29, 5/6,
290-298 |
71.05 |
0.04 |
17.8 |
1.4 |
0.01 |
0.01 |
0.01 |
|
5.27 |
4.36 |
Taaffeite |
reddish violet |
|
Sri Lanka |
The Journal of Gemmology 2005, 29, 5/6,
290-298 |
71.1 |
0.06 |
17.69 |
1.88 |
|
0.15 |
|
|
4.66 |
4.37 |
Zn-Taaffeite |
|
|
Sri Lanka |
Zeitschrift der Deutschen Gemmologischen
Gesellschaft, 1985, 34, Nr1/2, p22 |
71.1 |
0.06 |
17.69 |
1.88 |
|
0.15 |
|
|
4.66 |
4.4 |
Taaffeite |
greyish violet |
|
Sri Lanka |
Gems & Gemology 2000 Spring p52 |
72.12 |
0.02 |
20.92 |
2.1 |
0.01 |
0.01 |
0.01 |
0.04 |
0.11 |
4.46 |
Taaffeite |
purple |
|
Sri Lanka |
Gems & Gemology 2000 Spring p52 |
72.77 |
0.03 |
20.98 |
1.89 |
0.01 |
0.1 |
0.01 |
0.04 |
0.05 |
4.49 |
Taaffeite |
purple |
|
Sri Lanka |
Gems & Gemology 2000 Spring p52 |
72.62 |
0.04 |
19.4 |
2.21 |
0.01 |
0.11 |
0.01 |
0.03 |
0.59 |
4.43 |
Taaffeite |
reddish purple |
|
Sri Lanka |
Gems & Gemology 2000 Spring p52 |
71.12 |
0.03 |
19.71 |
2.05 |
0.02 |
0.14 |
0.02 |
0.04 |
2.11 |
4.4 |
Taaffeite |
reddish purple |
|
Sri Lanka |
Gems & Gemology 2000 Spring p52 |
72.9 |
0.04 |
20.52 |
1.37 |
0.01 |
0.13 |
0.01 |
0.03 |
0.09 |
4.46 |
Taaffeite |
reddish purple |
|
Sri Lanka |
Gems & Gemology 2000 Spring p52 |
72.62 |
0.02 |
20.73 |
1.54 |
0.01 |
0.13 |
0.01 |
0.02 |
0.55 |
4.47 |
Taaffeite |
purplish red |
|
Sri Lanka |
Gems & Gemology 2000 Spring p52 |
72.13 |
0.03 |
20.15 |
1.52 |
0.01 |
0.21 |
0.02 |
0.05 |
1.18 |
4.44 |
Taaffeite |
purplish red |
|
Sri Lanka |
Gems & Gemology 2000 Spring p52 |
71.88 |
0.03 |
19.71 |
2.59 |
0.02 |
0.18 |
0.01 |
0.04 |
0.38 |
4.42 |
Taaffeite |
purplish red |
|
Sri Lanka |
Gems & Gemology 2000 Spring p52 |
71.31 |
0.06 |
18.85 |
2.09 |
0.02 |
0.33 |
0.04 |
0.02 |
2.24 |
4.39 |
Taaffeite |
colour changing bluish to reddish |
|
Sri Lanka |
Zeitschrift der Deutschen Gemmologischen
Gesellschaft 1989, Aug, p90 |
73.33 |
0.001 |
20.43 |
1.82 |
|
0.03 |
|
0.05 |
0.11 |
|