|
INVESTIGATIONS
Stone |
RI min |
RI max |
Dens min |
Dens max |
Colour |
Location |
Info |
Spectrum |
UVS |
UVL |
Reference |
Tortoise shell |
1.54 |
1.54 |
1.26 |
1.35 |
|
|
aggregate-like under crossed polarisers; from the hawkshill turtle and
rarely the green turtle |
|
|
chalky blue-white (light areas), dark parts appear brown |
Gems & Gemology 2006 spring p36-52 |
Tortoise shell |
1.56 |
1.56 |
|
|
orange with brown patches |
|
a scepter of laminated tortoise shell, hot point test: burned protein |
|
blue |
strong blue |
Gems & Gemology 2016 Winter,
p419-420 |
TABLES
Stone |
RI min |
RI max |
Dens min |
Dens max |
Reference |
Tortoise shell |
1.53 |
1.586 |
1.26 |
1.35 |
Tables of Gemstone Identification, Roger Dedeyne, Ivo Quintens, 2007 |
Tortoise shell |
1.54 |
1.54 |
1.26 |
1.35 |
John Sinkakas, Gemstone and mineral data book,1972 |
Tortoise shell |
1.54 |
1.56 |
1.26 |
1.35 |
http://www.geminterest.com |
Tortoise shell |
1.54 |
1.54 |
1.26 |
1.35 |
Gems, R Webster, 5th edition 1994 |
Tortoise shell |
1.54 |
1.56 |
1.26 |
1.35 |
Gemology Tools Professional 2010 |
Tortoise shell |
1.54 |
1.56 |
1.25 |
1.31 |
Gemmo.eu 2017 |
Tortoise shell |
1.55 |
1.55 |
1.29 |
1.29 |
Gemmological Tables, Ulrich Henn,
2004 |
CAUSE OF
COLOUR
Stone |
Colour |
Cause
of colour |
Reference |
Tortoise shell |
yellow to brown |
charge transfer in organic products |
Gems & Gemology Summer 1988 |
CHEMICAL DATA
(%)