|
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 |
|
Cordierite |
1.52 |
1.541 |
|
|
2.57 |
2.57 |
colourless |
Embilipitiya, Sri Lanka |
|
|
|
|
|
|
|
|
|
|
Gems & Gemology 1996 winter,
p262-269 |
|
Cordierite |
1.52 |
1.541 |
0.01 |
0.01 |
2.57 |
2.57 |
nearly colourless |
Embilipitiya, Sri Lanka |
very Mg-rich |
|
|
|
|
|
|
|
|
|
The Australian Gemmologist 1986 Vol 16,
Nr 2, p35-40 |
|
Cordierite |
1.527 |
1.536 |
0.009 |
0.009 |
2.55 |
2.55 |
colourless |
Sri Lanka |
|
1.527 |
1.527 |
1.532 |
1.532 |
1.536 |
1.536 |
|
|
|
Zeitschrift der Deutschen Gemmologischen
Gesellschaft 1985 34, Nr1/2, p79-80 |
|
Cordierite |
1.528 |
1.54 |
|
|
2.548 |
2.554 |
red |
Iakora district, Fianarantsoa province, in southeast Madagascar |
1.28ct, 2.69ct and 4.17ct, Usambara effect, very strong pleochroism: deep
red to orange to greyish brown with a hint of blue or purple |
1.528 |
1.530 |
1.532 |
1.533 |
1.538 |
1.540 |
|
|
|
Gems & Gemology 2016 Spring, p 97 |
|
Cordierite |
1.529 |
1.538 |
0.009 |
0.009 |
2.55 |
2.55 |
brownish orange |
Iakora, Madagascar |
2.96ct |
|
|
|
|
|
|
|
inert |
very faint red |
http://www.spec4gem.info/index.php 2016 |
|
Cordierite |
1.529 |
1.538 |
0.009 |
0.009 |
2.62 |
2.62 |
blue |
Sri Lanka |
8.77ct |
|
|
|
|
|
|
no features |
inert |
inert |
GIA Gem Database 34802 |
|
Cordierite |
1.53 |
1.543 |
0.013 |
0.013 |
2.65 |
2.65 |
colourless |
|
3ct |
|
|
|
|
|
|
|
|
|
ACAM lab |
|
Cordierite |
1.53 |
1.54 |
0.01 |
0.01 |
2.53 |
2.55 |
orange-red to yellowish brown |
Madagascar |
2.55, 3.17 and 3.63ct |
1.530 |
1.530 |
1.533 |
1.534 |
1.540 |
1.540 |
strong band near 500nm |
inert |
inert |
The Journal of Gemmology 2016 Vol 35, No. 1, p 8-9 |
|
Cordierite |
1.531 |
1.54 |
0.009 |
0.009 |
2.65 |
2.65 |
colourless |
|
0.26ct |
|
|
|
|
|
|
|
|
|
ACAM lab
886 |
|
Cordierite |
1.531 |
1.541 |
0.01 |
0.01 |
2.62 |
2.62 |
colourless |
|
1.48ct, lamellar twinning |
1.531 |
1.531 |
1.534 |
1.534 |
1.541 |
1.541 |
|
inert |
inert |
Gems & Gemology 1998 winter, p
295-296 |
|
Cordierite |
1.531 |
1.542 |
0.009 |
0.009 |
2.59 |
2.6 |
greyish violet to violet |
Palmer Canyon, Laramie Mts, Wyoming |
0.36-1.33 ct |
1.531 |
1.533 |
|
|
1.540 |
1.542 |
no features |
|
|
Gems & Gemology 2001 Winter,
p336-337 |
|
Cordierite |
1.532 |
1.541 |
0.009 |
0.009 |
2.57 |
2.57 |
brown |
Madagascar |
|
|
|
|
|
|
|
band 490 |
inert |
inert |
Gems & Gemology 2004 winter, p328 |
|
Cordierite |
1.532 |
1.549 |
0.017 |
0.017 |
2.562 |
2.562 |
colourless |
|
0.26ct |
|
|
|
|
|
|
|
|
|
ACAM lab |
|
Cordierite |
1.532 |
1.548 |
0.016 |
0.016 |
2.59 |
2.59 |
colourless |
|
0.25ct |
|
|
|
|
|
|
|
|
|
ACAM lab
|
|
Cordierite |
1.532 |
1.55 |
0.018 |
0.018 |
2.59 |
2.59 |
violet |
|
|
|
|
|
|
|
|
|
|
|
ACAM lab
|
|
Cordierite |
1.532 |
1.546 |
0.01 |
0.012 |
2.55 |
2.57 |
blue |
Kragerö, Norway |
|
1.532 |
1.534 |
1.537 |
1.540 |
1.542 |
1.546 |
|
|
|
Zeitschrift der Deutschen Gemmologischen
Gesellschaft 1990 Sep, p99-106 |
|
Cordierite |
1.535 |
1.54 |
0.005 |
0.005 |
2.69 |
2.69 |
violet |
Beraketa, Toliara Province, Madagascar |
2.69ct |
|
|
|
|
|
|
broad absorption below 420nm |
inert |
inert |
GIA Gem Database 34405 |
|
Cordierite |
1.536 |
1.548 |
0.012 |
0.012 |
2.59 |
2.59 |
|
Madagascar |
1.33ct |
|
|
|
|
|
|
|
inert |
inert |
Gems & Gemology 1995 Spring, p62 |
|
Cordierite |
1.537 |
1.55 |
0.013 |
0.013 |
2.58 |
2.58 |
colourless |
Sri Lanka |
3.81ct |
|
|
|
|
|
|
|
|
|
Gemmologie, Zeitschrift der Deutschen
Gemmologischen Gesellschaft 1999 Jul p106 |
|
Cordierite |
1.538 |
1.549 |
0.011 |
0.011 |
2.575 |
2.575 |
violet |
|
2.36ct |
|
|
|
|
|
|
|
|
|
ACAM lab
|
|
Cordierite |
1.539 |
1.55 |
0.011 |
0.011 |
2.605 |
2.605 |
violet |
|
0.8ct |
|
|
|
|
|
|
|
|
|
ACAM lab
|
|
Cordierite |
1.539 |
1.546 |
0.007 |
0.007 |
2.58 |
2.58 |
violetish blue |
Mogok, Myanmar |
10.14ct |
|
|
|
|
|
|
line at 467nm |
inert |
inert |
GIA Gem Database 34555 |
|
Cordierite |
1.54 |
1.549 |
0.009 |
0.009 |
2.59 |
2.59 |
blue |
|
2.59ct |
|
|
|
|
|
|
|
inert |
inert |
ACAM lab
3850 |
|
Cordierite |
1.54 |
1.54 |
|
|
2.56 |
2.56 |
greyish blue |
|
cabochon, cat's-eye, translucent, 13.91ct, spot RI |
|
|
|
|
|
|
faint lines at 490 nm and 590nm |
|
|
Gems & Gemology 1982 Fall, p171 |
|
Cordierite |
1.547 |
1.515 |
0.037 |
0.037 |
2.56 |
2.56 |
dark orangy red |
|
|
|
|
|
|
|
|
|
|
|
Gems & Gemology 2017 Spring, p91-92 |
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 |
|
Cordierite |
1.522 |
1.578 |
0.008 |
0.012 |
2.53 |
2.78 |
1.522 |
1.558 |
|
|
1.524 |
1.578 |
Gemme, Dati per l'identificazione, P. De
Stefano et al, 1993 |
|
Cordierite |
1.522 |
1.578 |
0.005 |
0.018 |
2.53 |
2.78 |
|
|
|
|
|
|
http://www.gemmology.be |
|
Cordierite |
1.522 |
1.578 |
0.005 |
0.018 |
2.53 |
2.78 |
1.522 |
1.558 |
1.524 |
1.574 |
1.527 |
1.578 |
http://www.geminterest.com |
|
Cordierite |
1.522 |
1.578 |
0.005 |
0.018 |
2.53 |
2.78 |
1.522 |
1.558 |
1.524 |
1.574 |
1.527 |
1.578 |
Joel Arem, Color Encyclopedia of Gemstones,
1987 |
|
Cordierite |
1.522 |
1.578 |
0.005 |
0.02 |
2.53 |
2.78 |
1.522 |
1.558 |
1.524 |
1.574 |
1.527 |
1.578 |
Tables of Gemstone Identification, Roger Dedeyn, Ivo
Quintens, 2007 |
|
Cordierite |
1.522 |
1.596 |
0.005 |
0.018 |
2.56 |
2.66 |
|
|
|
|
|
|
Gemology Tools Professional 2010 |
|
Cordierite |
1.526 |
1.579 |
0.006 |
0.018 |
2.52 |
2.67 |
|
|
|
|
|
|
Gemmo.eu
|
|
Cordierite |
1.527 |
1.596 |
0.008 |
0.01 |
2.55 |
2.66 |
|
|
|
|
|
|
Bestimmungstabellen für Edelsteine,
Birgit Günther, 2008 |
|
Cordierite |
1.527 |
1.578 |
0.008 |
0.018 |
2.53 |
2.78 |
1.527 |
1.560 |
1.532 |
1.574 |
1.536 |
1.578 |
Gemmological Tables, Ulrich Henn,
2004 |
|
Cordierite |
1.53 |
1.55 |
0.008 |
0.012 |
2.57 |
2.66 |
1.530 |
1.540 |
|
|
1.540 |
1.550 |
Gems, R Webster, 5th edition 1994 |
|
Cordierite |
1.53 |
1.539 |
0.009 |
0.009 |
2.58 |
2.58 |
|
|
|
|
|
|
Tables of Gemstone Identification, Roger Dedeyn, Ivo
Quintens, 2007 |
|
Cordierite |
1.532 |
1.556 |
0.008 |
0.012 |
2.57 |
2.66 |
1.532 |
1.550 |
|
|
1.540 |
1.556 |
Tabellen zur Edelstein-Bestimmung,
Pschichholz FGA, 1975 |
|
Cordierite |
1.537 |
1.55 |
0.008 |
0.012 |
2.58 |
2.64 |
|
|
|
|
|
|
John Sinkakas, Gemstone and mineral data
book,1972 |
CAUSE OF
COLOUR
|
Stone |
Colour |
Cause
of colour |
Reference |
|
Cordierite |
violet, blue |
Fe˛+-O-Feł+ charge transfer, yellow // c-axis : Feł+ |
Gems & Gemology Summer 1988 |
|
Cordierite |
red (bloodshot iolite) |
hematite and or lepidocrocoite inclusions |
Gems & Gemology Summer 1988 |
MINERAL
INCLUSIONS
|
Inclusion |
Stone |
Reference |
|
apatite |
Cordierite |
Gemmological Tables, Ulrich Henn , GGA, 2004 |
|
hematite |
Cordierite |
Gemmological Tables, Ulrich Henn , GGA, 2004 |
|
ilmenite |
Cordierite |
E.J. Gübelin and J.I. Koivula, Photoatlas of inclusions in Gemstones,
volume 3 |
|
lepidocrocite |
Cordierite |
Internal World of Gemstones, Gübelin, 1983 |
|
magnetite |
Cordierite |
Internal World of Gemstones, Gübelin, 1983 |
|
mica |
Cordierite |
Gemmological Tables, Ulrich Henn , GGA, 2004 |
|
muscovite |
Cordierite |
E.J. Gübelin and J.I. Koivula, Photoatlas of inclusions in Gemstones,
volume 3 |
|
phlogopite |
Cordierite |
The Journal of Gemmology, 2016, Vol 35, No. 1, p 8-9 |
|
phlogopite |
Cordierite |
E.J. Gübelin and J.I. Koivula, Photoatlas of inclusions in Gemstones,
volume 3 |
|
pyrrhotite |
Cordierite |
E.J. Gübelin and J.I. Koivula, Photoatlas of inclusions in Gemstones,
volume 3 |
|
quartz |
Cordierite |
The Journal of Gemmology, 2016, Vol 35, No. 1, p 8-9 |
|
rutile |
Cordierite |
Gemmological Tables, Ulrich Henn , GGA, 2004 |
|
sillimanite |
Cordierite |
E.J. Gübelin and J.I. Koivula, Photoatlas of inclusions in Gemstones,
volume 3 |
|
tourmaline |
Cordierite |
The Journal of Gemmology, 2016, Vol 35, No. 1, p 8-9 |
|
zircon |
Cordierite |
Joel Arem, Color Encyclopedia of Gemstones, 1987 |
LOCALITIES
|
STONE |
LOCALITIES |
REFERENCE |
|||
|
Cordierite |
|
Nova Palmeira |
Paraiba |
Brazil |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Santa Barbara mine |
Parelhas |
Rio Grande do Norte |
Brazil |
Gems
& Gemology Spring 2005, p58 |
|
Cordierite |
|
Passmore |
British Columbia |
Canada |
InColor Fall-Winter 2007-2008 p24 |
|
Cordierite |
Slocan Valley |
Selkirk Mts |
British Columbia |
Canada |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Ghost Lake, Yellowknife |
Mackenzie District |
Northwest Territories |
Canada |
Natural History Museum Vienna collection |
|
Cordierite |
|
Tumkur |
Karanataka |
India |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Manmunda |
Boudh |
Orissa |
India |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Kantamal |
Boudh |
Orissa |
India |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Urharanga |
Kalahandi |
Orissa |
India |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Orhabahal |
Kalahandi |
Orissa |
India |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Burhapara |
Nawapada |
Orissa |
India |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Bommagoundamur |
Karur |
Tamil Nadu |
India |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Uthampatty |
Karur |
Tamil Nadu |
India |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Madurai District |
Madurai District |
Tamil Nadu |
India |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Ibity Mt |
Sahatany Valley |
Antananarivo |
Madagascar |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
|
|
Tuléar (Toliara) Province |
Madagascar |
Gemmologie, Dez 1999,p196 |
|
Cordierite |
|
Kragero |
Telemark |
Norway |
Zeitschrift der Deutschen Gemmologischen
Gesellschaft 1990, Sep, p99 |
|
Cordierite |
Avissawella |
Kegalla |
Central Proviince |
Sri Lanka |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
|
Kurunegala |
Central Proviince |
Sri Lanka |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Hatton |
Nuwara Elyia |
Central Province |
Sri Lanka |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Elahera |
Polonnaruwa |
Central Province |
Sri Lanka |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Ratnapura |
Ratnapura |
Sabaragamuwa province |
Sri Lanka |
Gems & Gemology 2000 winter p324 |
|
Cordierite |
Embilipitiya |
Monaragata |
Southern Province |
Sri Lanka |
Gems & Gemology 2000 winter p324 |
|
Cordieriet |
Palmer Canyon vermiculite deposit |
Albany County |
Wyoming |
USA |
Gems & Gemology 2001 Winter,p336 |
CHEMICAL DATA
|
Stone |
Colour |
Locality |
Reference |
SiO2 |
Al2O3 |
MgO |
FeO |
TiO2 |
CaO |
Na2O |
Fe2O3 |
K2O |
|
|
Cordierite |
almost colourless |
Embilipitiya |
Sri Lanka |
The Australian Gemmologist Feb 1986, Vol 16, Nr1, p3 |
49.51 |
32.98 |
12.64 |
0.95 |
0.02 |
0.01 |
0.08 |
0.14 |
0.01 |
|
Cordierite |
almost colourless |
Embilipitiya |
Sri Lanka |
The Australian Gemmologist Feb 1986, Vol 16, Nr1, p3 |
49.38 |
33.05 |
12.77 |
0.28 |
|
|
0.12 |
0.85 |
0.02 |
|
Cordierite |
almost colourless |
Embilipitiya |
Sri Lanka |
The Australian Gemmologist Feb 1986, Vol 16, Nr1, p3 |
49.31 |
33.08 |
11.47 |
0.98 |
|
|
0.1 |
|
0.01 |
|
Cordierite |
blue |
Kragerö |
Norway |
Zeitschrift der Deutschen Gemmologischen
Gesellschaft, 1990, Sep, p101 |
48.88 |
33.78 |
13.13 |
1.41 |
|
|
0.38 |
|
|
|
Cordierite |
blue |
Kragerö |
Norway |
Zeitschrift der Deutschen Gemmologischen
Gesellschaft, 1990, Sep, p101 |
47.52 |
32.9 |
12.8 |
1.43 |
|
|
0.37 |
|
|
|
Cordierite |
blue |
Kragerö |
Norway |
Zeitschrift der Deutschen Gemmologischen
Gesellschaft, 1990, Sep, p101 |
46.48 |
32.38 |
12.56 |
1.46 |
|
|
0.37 |
|
|
|
Cordierite |
blue |
Kragerö |
Norway |
Zeitschrift der Deutschen Gemmologischen
Gesellschaft, 1990, Sep, p101 |
47.14 |
32.9 |
12.81 |
1.68 |
|
|
0.4 |
|
|