|
INVESTIGATIONS
TABLES
|
Stone |
RI min |
RI max |
Dens min |
Dens max |
Reference |
|
Black
coral |
1.560 |
1.570 |
1.320 |
1.490 |
Bestimmungstabellen für Edelsteine, Birgit
Günther, 1981
|
|
Black
coral |
1.560 |
1.570 |
1.320 |
1.490 |
http://www.gemmology.be
|
|
Black
coral |
1.560 |
1.560 |
1.340 |
1.340 |
http://www.geminterest.com
|
|
Black
coral |
1.560 |
1.560 |
1.340 |
1.340 |
Gems, R Webster, 5th edition 1994
|
|
Black
coral |
1.560 |
1.570 |
1.320 |
1.490 |
Tables of Gemstone Identification, Roger Dedeyn,
Ivo Quintens, 2007
|
CAUSE OF COLOUR
|
Stone |
Colour |
Cause of
colour |
Reference |
|
Black
coral |
black |
various organic materials of unknown
nature |
Gems & Gemology Summer
1988 |
MINERAL INCLUSIONS
LOCALITIES