|
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 |
|
Coral |
1.495 |
1.65 |
0.145 |
0.15 |
2.37 |
2.75 |
|
|
CALCITIC corals (biogenetic calcit has a high Mg
content => RI between calcite and
magnesite |
|
|
|
|
|
|
|
|
|
The Australian Gemmologist 2005 22/7 Jul/Sep
p285-297 |
|
Coral |
1.52 |
1.65 |
0.13 |
0.13 |
|
|
|
|
ARAGONITE corals (biogenetic aragonite has a
high Sr content => RI between aragonite and
strontianite |
1.520 |
1.520 |
|
|
1.650 |
1.650 |
|
|
|
The Australian Gemmologist 2005 22/7 Jul/Sep
p285-297 |
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 |
|
Coral |
1.486 |
1.658 |
0.172 |
0.172 |
2.6 |
2.7 |
|
|
|
|
|
|
Bestimmungstabellen für Edelsteine, Birgit
Günther, 1981
|
|
Coral |
1.486 |
1.69 |
0.16 |
0.172 |
2.6 |
2.7 |
|
|
|
|
|
|
Gemme, Dati per l'identificazione, P. De Stefano
et al, 1993
|
|
Coral |
1.486 |
1.658 |
0.172 |
0.172 |
2.6 |
2.7 |
|
|
|
|
|
|
Gemmological Tables, Ulrich Henn, 2004
|
|
Coral |
1.486 |
1.69 |
0.16 |
0.172 |
2.6 |
2.7 |
|
|
|
|
|
|
http://www.gemmology.be
|
|
Coral |
1.486 |
1.69 |
0.16 |
0.16 |
2.6 |
2.7 |
|
|
|
|
|
|
Tables of Gemstone Identification, Roger Dedeyn,
Ivo Quintens, 2007
|
|
Coral |
1.49 |
1.69 |
0.16 |
0.2 |
2.6 |
2.7 |
|
|
|
|
|
|
http://www.geminterest.com
|
|
Coral |
1.49 |
1.69 |
0.16 |
0.16 |
2.6 |
2.7 |
|
|
|
|
|
|
Joel Arem, Color Encyclopedia of Gemstones,
1987
|
|
Coral |
1.56 |
1.57 |
|
|
|
|
|
|
|
|
|
|
Gemme, Dati per l'identificazione, P. De Stefano
et al, 1993
|
|
Coral |
1.57 |
1.57 |
|
|
2.61 |
2.7 |
|
|
|
|
|
|
John Sinkakas, Gemstone and mineral data
book,1972
|
CAUSE OF COLOUR
|
Stone |
Colour |
Cause of
colour |
Reference |
|
Coral |
blue (heliopora
caerulea) |
organic pigment from the bilins
family |
Gems & Gemology Summer
1988 |
|
Coral |
red to
pink |
organic pigment from the carotenoid family, at
least for Corallum rubrum |
Gems & Gemology Summer
1988 |
MINERAL INCLUSIONS
LOCALITIES
CHEMICAL DATA